TK 


JC-NRLF 


GIFT  OF 


LJEXLIBMSB 


Factories:  ANSONIA,  CONN. 


lljires,  Cables,  Conductor  (jords, 

METALS,    ETC. 

*     '     * 

Bare  Copper  Wire. 

Galvanized  'Iron  Wire. 
Brass  Wire. 

German  Silver  Wire. 
Phosphor  Bronze  Spring  Wire. 
Platinum  Wire. 

Pressure  Wire. 

Underwriters'   Wire. 
P.  &  B.   Weather-proof  Wire. 

Kerite  Insulated  Wires  and  Cables. 
Incandescent    Electric    Light  Elevator 

Cables. 
Cables,  all  sizes,  either   Underwriters' 

or  D.  B.  and  Paraffine  insulation. 
Conductor  Cords. 

Magnet   Wire. 

Brass  and  Copper  Sundries. 

WRITE    FOR    CATALOGUE. 

The  Electrical  Supply  C°*> 

171     RANDOLPH    STREET,    CHICAGO. 

Branch,  125  W.  6th  St.,  KANSAS  CITY,  MO. 

Factories:    ANSONIA,    CONN. 


DYNAMO  TENDERS' 

#  t 

HAND-BOOK, 

WITH  SEVENTY  ILLUSTRATIONS. 


BY 

F.     B.     BADT, 

Late  First  Lieutenant  floyal  Prussian  Artillery. 


FOURTH  EDITION. 


ELECTRICIAN  PUBLISHING  COMPANY, 

CHICAGO,  ILL. 


COPYRIGHT,  1891. 

BY 
ELECTRICIAN    PUBLISHING    COMPANY, 

ALL  RIGHTS   ^ESERVEDo 


PREFACE  TO  THE  FIRST  EDITION. 

EACH  company  manufacturing  electric  light  apparatus 
furnishes  special  directions  for  its  care  and  management, 
and  hence  a  general  knowledge  of  the  principles  governing 
the  construction  and  operation  of  electric  light  installations 
has  been  obtainable  only  by  a  practical  observation  of  the 
features  of  each  system  or  by  study  of  books  so  technical 
in  character  as  to  be  beyond  the  comprehension  of  those 
not  possessing  an  academical  or  collegiate  education. 

Therefore,  in  the  preparation  of  DYNAMO  TENDERS* 
HAND-BOOK,  the  author  has  striven  to  lay  down,  as  the 
results  of  an  extended  experience,  general  rules  for  the 
care  and  operation  of  electric  light  installations  and  dis- 
carding entirely  the  use  of  technical  phraseology  and  scien- 
tific terms  and  formulae,  has  endeavored  to  confine  his  use 
of  words  to  those  very  plain,  simple  and  elementary  in 
character. 

To  dynamo  tenders,  engineers,  linemen  and  others  who 
wish  to  familiarize  themselves  with  the  principles  underly- 
ing the  care  and  operation  of  electric  light  installations, 
this  hand-book  is  offered  with  the  hope  that  the  author's 
intentions  have  been  carried  out  to  the  full. 

To  those  who  wish  to  pursue  the  study  of  the  principles 
of  electric  lighting  into  deeper  channels,  the  author  cor- 
dially recommends  "Elementary  Lessons  in  Electricity  and 
Magnetism,"  by  Silvanus  P.  Thompson;  "Electric 
Light  Arithmetic,"  by  R.  E.  Day;  "  Magneto  Electric 
and  Dynamo  Electric  Machines,"  by  Dr.  H.  Schellen; 
Munro  &  Jamieson's  "Pocket-Book  of  Electrical  Rules 
and  Tables." 


PREFACE  TO   THE  SECOND   EDITION. 

THE  great  demand  for  the  DYNAMO  TENDERS'  HAND- 
BOOK has  compelled  the  author  to  prepare  a  second  edition. 
He  has  corrected  several  errors  of  the  first  edition,  and 
added  the  new  Rules  and  Regulations  for  Overhead  Con- 
ductors for  Electric  Light  and  Power  established  by  the 
Board  of  Electrical  Control  of  New  York,  and  attached  the 
Lamp  Lighting  schedule  for  1889. 

F.  B.  BADT. 

Chicago,  111.,  December,  1888. 


464531 


CONTENTS. 


ELEMENTARY  DATA—  PAGE. 

The  Electric  Current,  Chapter  I ..,».,, . I,  2 

Ohm's  Law,  Chapter  II . 2 

Work,  Chapter  III... 2 

Conductors  and  Insulators,  Chapter  IV ...  2 

Direction  of  the  Current,  Chapter  V 3,  4 

Detector    Galvanometer    and     Magneto    Bell, 

Chapter  VI _ 5,  6,  7 

ARRANGEMENT  OF  POWER — 

The  Dynamo  Room,  Chapter  VII 8 

Motive  Power,  Chapter  VIII- 8 

Shafting  and  Pulleys,  Chapter  IX 9 

Foundations  for  Dynamos,  Chapter  X _,  9,   10 

Belts,  Chapter  XI 10 

DYNAMO  ELECTRIC  MACHINES— 

Description  of  the  Dynamo,  Chapter  XII II 

The     Continuous    Current     Dynamo,     Chap- 
ter XIII n,   12,   13,   14 

The  Series  Dynamo-- u,   12 

The  Shunt  or  Derived  Circuit  Dynamo.-.  12,   13 

The  Compound  Dynamo  .*. 13,   14 

The     Alternating     Current    Dynamo,    Chap- 
ter XIV  14,   15 

Preparation  of  a  New  Dynamo  for  Operation, 

Chapter  XV 15,   16 

Starting  a  New  Dynamo,  Chapter  XVI 16 

Keeping   a   Dynamo   in   Good    Order,    Chap- 
ter XVII 17 


CONTENTS. 

Brushes,  Chapter  XVIII 17,  18,  19 

The  Commutator,  Chapter  XIX 19,  20 

Repairs,  Chapter  XX 20,  21 

To  the  Armature _ _ 20,  21 

To  the  Field  Magnets 21 

Testing  the  Wire  Coils  of  a  Dynamo  for  Con- 
tact Against  Iron,  Chapter  XXI. .     21,   22,   23,  24 

DISEASES  OF  DYNAMOS — 

Non-generation    of   Current   by  the    Dynamo, 

Chapter  XXII _ 25,   26 

Excessive  Sparking  of  Commutator  and  Brushes, 

Chapter  XXIII 26,  27 

LAMPS — 

Arc  Lamps,  Chapter  XXIV 28,   29,   30,   31 

Suspension  of  Arc  Lamps,  Chapter  XXV_ 31 

Trimming   and    Cleaning   Arc    Lamps,   Chap- 
ter XXVI 32 

Incandescent  or  Glow  Lamps,  Chapter  XXVII .  32,  33 

Multiple  Arc  System,  Chapter  XXVIII- 33 

Multiple  Series  System,  Chapter  XXIX. _     33,  34,  35 

Series  Multiple  System,  Chapter  XXX 36 

Arc  and  Incandescent  Lamps  on  the  Same  Cir- 
cuit, Chapter  XXXI. __ .36,  37,   38 

The  Alternating  System,  Chapter  XXXII 38 

INSTRUMENTS — 

Current    Indicator   or    Ampere    Meter,    Chap/ 

ter  XXXIII 39 

Pressure  or  Potential  Indicator,  or  Voltmeter, 

Chapter  XXXIV  _ 39,  40 

Current  Regulator,  Chapter  XXXV 40,  41 

Switches,  Chapter  XXXVI _ .41,  42 

Safety  Devices,  Chapter  XXXVII 42,  43 

Lightning  Arresters,  Chapter  XXXVIII 43,  44 

Ground  Detector,  Chapter  XXXIX ._-  45,  46 

Switch-Board,  Chapter    XL_ 46,  47 


CONTENTS. 

CIRCUITS  OR  LEADS— 

Outdoor  Leads  for  Arc  Lighting,  Chap- 
ter XLI 48,  49,  50,  51,  52,  53 

Outdoor  Leads  for  Incandescent  Lighting, 

Chapter  XLII 53,  54 

Arc  Circuits  Inside  of  Houses,  Chapter  XLIII         54 

Incandescent  Circ  uits  Inside  of  Houses,  Chap- 
ter XLIV 55,  56,  57 

Size  of  Wires  for  Incandescent  Lamp  Installa- 
tioas,  Chapter  XLV 57,  58,  70 

Testing,  Chapter  XLVI 58 

ACCUMULATORS — 

Accumulators,  Chapter  XLVII 59 

SAFETY  REGULATIONS — 

Rules  of  the  Boston  Underwriters'  Union 

60,  61,  62,  63,64,  65,  66 

English  Regulations 66,  67,  68 

Abstract  of  the  Chicago  Electric  Light  Laws. .  68,  69 
Rules  and  Regulations  of  the  New  York  Board 
of  Electrical  Control 69,  70,  71,  72,  73 


Table  of  Electric  Light  Conductors 74 

Lamp  Lighting  Schedule — Moonlight  System.. .  75-86 
Construction  Tools ••••  87-93 


ELEMENTARY   DATA. 


CHAPTER  I. 
The  Electric  Current. 

Tn  order  to  understand  the  action  of  what  is  called  the 
electric  current,  we  will  consider  two  reservoirs  of  water 
connected  by  a  pipe,  Fig.  I.  The  electric  current  may  be 
likened  to  the  flow  of  water  through  this  pipe  from  the 
higher  to  the  lower  level. 

The  unit  of  current  strength,  also  called  the  rate  of  flow, 
or  intensity,  is  the  ampere.  In  the  illustration  we  would 


FIG.  i.  —  RESERVOIRS  OF  WATER. 

say  the  water  is  flowing  through  the  pipe  at  the  rate  of  one 
gallon  per  second.  In  speaking  of  the  electric  current  we 
would  say  it  has  a  strength  of,  say,  one  ampere. 

The  unit  of  electromotive  force,  also  called  electrical 
pressure,  or  tension,  or  difference  of  potential,  is  the  volt. 
In  the  illustration  the  head  of  water,  or  the  difference  be- 
tween the  levels  A  and  B  is  similar  to  the  electromotive 
force. 

The  unit  of  resistance  is  the  ohm.  Resistance  may  be 
compared  with  the  friction  of  the  internal  surface  of  the 
pipe  offered  to  the  water.  It  follows  that  the  more  cross- 
section  the  less  friction,  and  the  less  cross-section  the  more 
friction,  for  the  same  volume  of  water  flowing  through  the 
pipe  in  a  given  time. 


UAXD-BOOK. 

In  the  following,  only  the  terms,  current  strength,  elec^ 
tromotive  force — frequently  written  e.m.f. — and  resistance, 
will  be  used. 

CHAPTER  II. 
Ohm's  Law. 

Ohm's  law  expresses  the  relation  of  current  strength, 
electromotive  force,  and  resistance,  to  each  other.  It  says  : 
Current  strength  equals  electromotive  force  divided  by 

j? 
resistance.     We  can  write  this  C  =  — ,  C  standing  for  cur- 

R 

rent  strength,  E  for  electromotive  force,  and  R  for  resist- 
ance. 

CHAPTER  III. 
Work. 

The  work  accomplished  by  electricity  is  expressed  in 
volt-amperes  or  watts.  The  product  of  so  many  gallons 
per  second  and  the  difference  between  the  two  levels  B  and 
A,  would  give  us  the  work  accomplished  by  the  water  in 
illustration,  Fig.  I.  The  same  work  can  be  done  with 
great  current  strength  and  low  e.m.f.,  or  with  small  current 
strength  and  high  e.m.f.  For  instance,  100  amperes  x  10 
volts  =  equals  1,000  watts;  or,  10  amperes  x  100  volts  = 
1,000  watts. 

One  electrical  horse  power  equals  746  watts  ;  hence  the 
electrical  work  of  a  dynamo  may  be  expressed  : 

H.   P.  =f  mperes   x  vote      The  number  of  mechanical 

746. 

horse  power  necessary  to  drive  a  dynamo  is  generally  10  to 
20  per  cent,  higher  than  the  electrical  horse  power  yielded 
b"  the  dynamo. 

CHAPTER   IV. 
Conductors    and    Insulators. 

Bodies  in  which  the  current  moves  freely  are  called  con- 
ductors, and  those  in  .which  it  does  not  move  freely  are 
called  insulators.  Examples  of  conductors  :  Metals,  solu- 
tions of  chemical  salts,  moist  earth,  etc.  Examples  of  insu- 
lators :  Porcelain,  rubber,  gutta  percha,  sealing  wax,  dry 
wood,  etc. 


ELEMENTARY  DATA.  3 

CHAPTER   V. 
Direction  of  the  Current. 

For  convenience  sake  we  assume  that  the  electric  current 
flows  from  the  positive  pole  of  a  galvanic  cell  or  any 
other  generator  of  electricity,  through  the  external  circuit 
back  to  the  negative  pole.  In  order  to  find  the  direction  in 
which  the  current  is  passing  through  the  wire,  we  place  a 
pocket  compass,  Fig.  2,  under  \h&  wire,  Fig.  3.  The  north- 
seeding  pole  of  the  needle,  called  the  north  pole,  and  dis- 


FIG.  2.  —  POCKET  COMPASS. 

tinguishetf  either  by  a  different  color — blue,  for  instance — 
or  by  a  littte  brass  rivet,  will  be  deflected  to  t  e  left  when 
the  current  flows  in  the  direction  of  the  arrow,  Fig.  3.  Or, 
in  other  words,  the  positive  electricity  enters  at  A  and 
leaves  at  B. 

When  the  compass  is  held  above  the  wire  the  nprth  pole 
of  the  needle  will  be  deflected  to  the  right. 

General  rule  :  Think  yourself  swimming  in  the  current 
always  facing  the  needle.  The  positive  current  entering  at 
your  feet  will  cause  the  needle  to  deflect  to  your  left. 

Another  general  rule:  Think  of  the  word  Snow.  With  the 
wire  over  the  compass  the  current  flowing  from  the  South 
to  the  North  will  deflect  the  needle  to  the  West ;  in  other 
words,  from  S-outh  to  N-orth  O-ver  W-est. 

The  compass  should  be  tested  before  these  trials  are 
made,  as  the  polarity  may  have  been  reversed  by  the  prox- 
imity of  dynamo  electric  machines  or  other  powerful 
magnets. 


DYNAMO    TE  *?£>£ 


The  binding  post  of  the  dynamo  electric  machine  or  bat- 
tery from  which  the  current  starts  is  called  the  positive  and 
is  marked  +  ;  the  opposite  binding  post  is  called  the  nega- 
tive and  is  marked  —  .  All  indicators,  lamps  and  other  ap- 
paratus which  are  connected  in  the  electric  circuit  must  be 


FIG.  3.  —  COMPASS  UNDER  THE  WIRE, 

marked  accordingly  ;  the  binding  post  which  should  be 
connected  with  the  positive  binding  post  of  the  dynamo 
with  +  and  the  other  with  —  .  There  are  quite  a  number 
of  instruments  and  electrical  apparatuses,  such  as  incandes- 
cent lamps,  for  instance,  which  may  be  inserted  in  the 
circuit  either  way.  These,  of  course,  need  not  be  marked 
at  all. 


CLEMEN  TAR  Y  DA  TA.  5 

CHAPTER  VI. 
Detector  Galvanometer  and  Magneto  Bell. 

The  detector  galvanometer,  Fig.  4,  in  connection  with 
the  galvanic  cell,  Fig.  5,  is  used  for  testing  the  insulation 
of  the  wires  and  apparatus  and  for  locating  other  faults. 
The  detector  galvanometer  is  a  compass  mounted  on  a  coil 
of  wire.  An  electric  current  passing  through  this  coil  will 
deflect  the  needle  of  the  compass,  as  has  been  explained  in 
Chapter  V.  Of  course,  a  coil  will  cause  a  greater  deflec- 
tion of  the  needle  than  a  single  wire  as  the  current  is 
forced  to  pass  a  number  of  times  under  the  needle. 


FIG.  4.  —  DETECTOR  GALVANOMETER. 
In  order  to  test  for  insulation  with  the  galvanometer, 
connect  the  galvanometer  and  the  galvanic  cell  in  series, 
that  is,  tandem— one  behind  the  other,  Fig.  6 — and  connect 
one  wire  starting  from  binding  post  A  to  aground — gas  pipe 
or  water  pipe  —  and  the  other  starting  from  B  to  the  wire 
to  be  tested  for  insulation.  If  the  needle  deflects,  the  wire 
is  grounded  ;  if  it  remains  in  its  position  the  insulation  is 
in  good  condition.  It  is  well  to  connect  wires  A  and  B 
for  a  minute  before  testing,  and  see  whether  cell  and  gal- 
vanometer are  in  good  condition.  In  connecting  the  wires 
the  insulation  must  be  carefully  removed  and  the  wire  per- 
fectly cleaned  by  scraping  with  a  knife  or  by  rubbing 
with  a  piece  of  emery  cloth.  Connections  must  always  be 


6          DYNAMO    TENDERS'  HAND-BOOK. 

made  with  clean  metallic  surfaces.  In  the  same  way 
a  break  in  the  circuit  can  be  found.  Cut  the  cir- 
cuit in  several  sections  and  connect  the  ends  of 


FIG.  5.  — GALVANIC  CELL. 

each  section  to  A  and  B.  When  the  needle  deflects,  there 
is  no  break  in  the  circuit ;  if  it  does  not  deflect,  the  circuit 
is  open. 


FIG.  6. —  GALVANOMETER  AND  CELL  CONNECTED. 


ELEMENTARY  DATA. 


Fig.  7  shows  one  form  of  portable  galvanometer,  com- 
bining galvanometer,  battery  and  wire. 

Very  often  a  magneto  bell,  Fig.  8,  similar  to  that  used  as 
a  call  for  telephones,  is  employed  for. testing.  When  the 
bell  rings  the  circuit  is  closed;  if  it  does  not  ring  the  cir- 


FIG.   7.  —  PORTABLE 


GALVANOMETER, 
WIRE. 


BATTERY    AND 


cuit  is  open.     This  is  all  it  can   tell 


while  the  detector  gal- 
vanometer, if  proper- 
ly handled,  can  tell 
very  much  more.  A 
detector  galvanome- 
ter can  be  carried  in 
the  pocket  and  rarely 
gets  out  of  order, 
and  a  galvanic  cell 
can  be  had  almost 
anywhere  A  mag- 
neto bell  is  a  bulky 
apparatus  and  liable 
to  get  out  of  order  at 
any  time.  The  use 
of  the  galvanometer 
is  preferable. 

A  test  with  a  cell 
and  an  ordinary  elec- 
tric   bell    cannot    be 
considered  reliable. 
FIG.  8.—  MAGNETO  BELL.  Such  a  bell  will  ring 

only  through  a  very  low  resistance,  while  a  good  magneto 
bell  will  ring  through  from  10,000  to  20,000  ohms  resist- 
ance and  a  high  resistance  galvanometer  with  a  powerful 
battery  will  deflect  through  millions  of  ohms  of  resistance. 


ARRANGEMENT  OF  POWER. 


CHAPTER  VII. 
The  Dynamo  Room. 

It  is  best  to  have  a  separate  room  for  the  dynamo  and 
the  motive  power,  which  generally  consists  of  a  steam 
engine.  If  more  than  one  dynamo  is  to  be  used,  it  is  also 
preferable  to  have  them  all  in  one  room,  as  one  man  can 
more  readily  attend  to  them.  The  place  where  the  dynamo 
is  to  be  located  should  be  dry  and  free  from  dust.  A 
turning  lathe  should  not  be  allowed  near  a  dynamo,  nor 
should  the  man  in  charge  be  allowed  to  file  iron  in  its 
proximity. 

CHAPTER  VIII. 
Motive  Power. 

The  main  thing  to  be  considered  in  selecting  an  engine 
for  an  electric  light  plant  is  uniform  speed.  Any  fluctua- 
tion in  the  speed  of  the  engine  will  show  in  the  lights. 
Incandescent  lights  are  more  sensitive  in  this  respect  than 
arc  lights.  It  is  preferable  to  have  an  extra  engine  for  the 
electric  light  machinery.  If  other  machinery  is  connected 
with  the  engine,  the  sudden  throwing  on  and  off  of 
machines  will  cause  an  irregular  speed  of  the  dynamo  and 
very  disagreeable  fluctuations  in  the  lights.  The  best 
power  so  far  known  to  run  electric  light  machinery  is  the 
modern  automatic  cut-off  steam  engine.  The  regulation 
of  water  motors,  turbine  wheels,  etc.,  and  gas  motors,  is 
generally  not  very  satisfactory  for  electric  light  plants. 

A  good  instrument  for  indicating  the  speed  of  a  shaft  or 
a  dynamo  at  all  times  is  the  tachometer.  It  will  show 
variations  even  within  a  small  fraction  of  a  minute. 


ARRANGEMENT  OF  POWER.  g 

CHAPTER  IX. 
Shafting  and  Pulleys. 

The  number  of  shafts  should  be  reduced  to  a  minimum. 
It  is  very  convenient  to  use  friction  pulleys,  if  more  than 
one  dynamo  is  to  be  driven  from  the  same  shaft  ;  by  means 
of  friction  pulleys  any  dynamo  can  be  thrown  in  or  out  at 
will.  In  calculating  the  diameter  of  the  pulleys,  it  should 
be  borne  in  mind  that  there  is  always  a  loss  in  speed  caused 
by  the  slippage  of  the  belt. 

It  is  safe  to  allow  about  2  per  cent,  for  slippage  for 
each  belt.  It  is  advisable  to  have  the  distance  between  the 
driving  shaft  and  the  shaft  of  the  dynamo  not  too  short. 

A  long  belt  will  generally  give  better  results  than  a  short 
belt.  The  bearings  will  keep  cooler,  less  oil  will  be  used, 
and  even  with  comparatively  slack  belts  there  will  be  little 
slippage. 

On  the  other  hand,  short  belts  must  be  drawn  very  tight 
to  prevent  slippage.  The  boxes  will  heat,  oil  will  be  con- 
sumed faster,  and  the  belts  will  be  short  lived. 

Vertical  belts  must  not  be  allowed  ;  horizontal  belts  give 
the  best  results.  Arrange  the  shafting  to  get  the  belts  at 
an  angle  of  at  least  40  degrees  with  a  vertical  line. 

If  possible  arrange  to  have  the  slack  side  of  belt  on  top. 

CHAPTER     X. 
Foundations  for  Dynamos. 

A  dynamo  should  be  solidly  set.  Vibration  caused  by 
the  rotation  of  the  armature  on  a  poor  foundation  may 
cause  damages  to  dynamos  in  various  ways.  Especially 
larger  dynamos,  say  from  twenty-five  horse  power  upwards, 
should  be  set  on  a  solid  brick  or  stone  foundation. 

The  iron  frame  of  a  dynamo  should  be  properly  insulated 
from  such  foundations  ;  this  is  generally  done  by  a  dry 
wood  base  plate.  The  upper  surface  of  this  brick  or  stone 
foundation  should  be  at  least  one  foot  above  the  floor;  this 
will  enable  the  engineer  or  dynamo  tender  to  keep  the 
machine  free  from  dirt,  and  will  facilitate  the  inspection  of 
the  bearings,  the  commutator,  and  other  important  parts. 

In  a  place  where  the  noise  caused  by  dynamos  and 
engines  would  be  objectionable,  it  is  of  importance  to  keep 
*he  foundations  away  from  the  foundation  walls  of  the 


io        DYNAMO    TENDERS'  HAND-BOOK. 

building.  The  counter-shafts  must  be  set  on  the  floor, 
and  the  floor  above  the  dynamo  room  should  be  deadened. 
Most  dynamos  are  provided  with  a  frame  and  a  belt- 
tightening1  apparatus,  which  can  be  set  on  the  foundation 
without  any  further  preparations. 

CHAPTER  XI. 
Belts. 

The  best  belt  to  drive  dynamo  electric  machinery  is  a 
light,  double,  endless,  and  rivetless  leather  belt.  A  single 
belt  may  be  used  for  small  dynamos,  say,  under  ten  horse 
power.  Belts  should  always  be  made  endless.  A  laced 
joint  will  show  a  fluctuation  in  the  light  every  time  it 
passes  over  the  dynamo  pulley. 

It  is  advisable  to  run  a  new  dynamo  a  day  or  two  with  a 
loose  belt.  In  taking  the  measurement  for  a  belt,  the 
dynamo  should  be  moved  by  means  of  the  belt-tightener  as 
near  the  driving  pulley  as  possible;  when  this  is  done,  it 
will  be  possible  to  utilize  the  whole  length  of  the  belt- 
tightener  screw  to  stretch  the  belt.  A  belt  should  never  be 
tightened  any  more  than  enough  to  prevent  an  excess  of 
slippage.  Any  belt  will  slip  a  little,  but  this  slippage 
should  not  exceed  2  per  cent, 


DYNAMO     ELECTRIC 
MACHINES. 


CHAPTER  XII. 
Description  of  the  Dynamo. 

A  dynamo  consists  of  the  field  and  the  armature.  The 
field  consists  of  the  magnets,  which  are  solidly  connected 
with  the  iron  frame.  The  magnets  are  iron  cores,  on 
which  layers  of  insulated  wire  are  wound.  These  magnets 
belong  to  the  class  of  electro-magnets,  as  they  become 
magnetic  only  when  the  current  is  passing  through  their 
coils.  Between  the  poles  of  the  magnet  the  armature 
rotates.  The  armature  consists  of  an  iron  or  steel  shaft,  to 
which  a  number  of  coils  of  insulated  wire  are  affixed. 

Metal  plates  or  bundles  of  wire  called  brushes  conduct 
the  current  generated  in  the  armature  to  the  lamp  circuit. 

The  two  main  types  of  dynamos  are  : 

A,  The  continuous  current  dynamo.  The  current  gener- 
ated in  this  dynamo  always  flows  in  the  same  direction. 
The  armature  of  this  dynamo  has  a  commutator  from  which 
the  current  is  taken  off  by  the  brushes. 

By  The  alternating-  current  dynamo.  The  current  gene- 
rated in  this  machine  flows  at  rapid  intervals  first  in  one 
and  then  in  the  other  direction.  This  dynamo  has  no  com- 
mutator but  simply  a  collector  consisting  of  two  metal  rings 
on  which  the  brushes  rest.  The  magnets  of  the  alternating 
current  machine  require,  however,  a  continuous  current 
for  excitation.  This  current  is  generated  by  an  extra  con- 
tinuous current  machine  of  small  size,  which  is  called  the 
exciter. 

CHAPTER  XIII. 
The  Continuous  Current  Dynamo. 

A,  The   series  dynamo,  Fig.  9.     Magnet,  armature  and 
lamp  circuit  are  connected  one  behind  the  other,  that  is,  in 
II 


12        DYNAMO    TENDERS'  HAND-BOOK. 

series  ;  that  is  to  say,  the  current  generated  in  the  armature 
passes  in  equal  strength  through  field  magnets  and  lamp 
circuit.  These  machines  are  mostly  used  for  arc  lighting. 


FIG.  9.  —THE  SERIES  DYNAMO. 


B%  The  shtmt  dynamo,  also  called  derived  circuit  dynamo. 
The  coils  of  wire  wound  around  the  field  magnets  in  this 
machine,  Fig.  10,  are  connected  in  shunt  or  parallel  to  the 
brushes.  Only  a  comparatively  small  part  of  the  current 
generated  in  the  armature  is  used  for  excitation  of  the  field 
coils,  while  the  greater  part  of  the  current  is  conducted 
from  the  brushes  to  the  lamp  circuit.  These  machines  gen- 
erally have  a  resistance  box,  rheostat  or  regulator  which  is 
connected  in  the  shunt  winding  of  the  field.  By  putting 
more  or  less  resistance  in  the  field  of  these  machines  the 
e.  m.  f .  at  the  binding  post  of  the  machine  can  be  decreased 


DYNAMO  ELECTRIC  MACHINES.          13 

or  increased.  Shunt  dynamos  are  mostly  used  for  incan- 
descent lighting.  In  some  systems,  however,  they  are  used 
for  arc  lighting  also. 

C,  The  Compound  Dynamo.  This  dynamo,  Fig.  II, 
combines  in  its  fields  the  winding  of  both  the  series  and 
the  shunt  dynamo.  The  magnets  are  wound  with  thick 


FIG.  10. —  THE  SHUNT  DYNAMO. 


wire,  which  is  in  series  with  the  armature  and  the  lamp  cir- 
cuit. In  addition  they  have  a  winding  of  fine  wire,  which 
is  in  shunt  with  the  brushes.  This  dynamo  generally  has 
a  resistance  box  put  in  the  shunt  winding  of  the  fields,  for 


14 


DYNAMO   TENDERS'   HAND-BOOK. 


the    same   purpose   as    explained    under   B.      Compound 
dynamos  are  mostly  used  for  incandescent  lighting. 


FIG.  ii.  —  THE  COMPOUND  DYNAMO. 

CHAPTER  XIV. 
The  Alternating  Current  Dynamo. 

The  field  wire  coils  of  an  alternating  currrent  dynamo, 
Fig.  12,  have  no  connection  with  the  brushes  of  the  dynamo 
at  all.  The  fields  are  separately  excited,  as  mentioned  in 
the  foregoing,  by  a  little  continuous  current  dynamo,  called 
an  exciter  The  alternating  current  machines  were  used 
formerly  for  arc  lighting  mainly  —  very  little,  however,  in 
the  United  States — but  recently  have  been  introduced  for 
long  distance  incandescent  lighting  by  means  of  trans- 
formers or  converters. 


DYNAMO  ELECTRIC  MACHINES.          15 

CHAPTER  XV. 

Preparation   of  a   New    Dynamo   for 
Operation. 

Iron  par's  which  have  to  be  fitted  to  each  other  must  be 
carefully  cleaned  with  fine  emery  cloth.  When  the  arma- 
ture is  put  into  the  dynamo,  extra  precaution  is  necessary 
in  order  to  avoid  any  injuries  to  the  insulation  of  the  wire 
and  to  the  commutator.  The  armature  should  be  carried 
by  a  man  on  each  end  of  the  shaft.  Heavy  armatures 


FIG.  12. —  THE  ALTERNATING  CURRENT  DYNAMO. 
should  be  supported  by  a  board  put  underneath  the  arma- 
ture, and  each  end  carried  by  an  additional  man.     Arma- 
tures weighing   over  500   pounds   should   be  handled   by 
means  of  a  differential  block  and  tackle. 

An  armature  should  not  be  lifted  by  its  commutator. 

Some  soft   material,    such  as   cotton   waste  or  felting, 
should  be  put  between  the  armature  and  the  support. 


16        DYNAMO    TENDERS'  HAND-3OOK. 

When  put  in  place  in  the  dynamo  the  armature  must  not 
touch  the  pole  pieces  and  must  turn  easily.  There  should 
be  at  least  from  -£$  to  l/%  inch  play  between  its  bearings. 
This  play  or  lengthways  motion  can  generally  be  regulated 
by  adjusting  the  collar  on  the  shaft. 

It  must  be  borne  in  mind  that  the  armature  will  warm 
and  expand  not  only  diametrically  but  also  lengthways.  If 
there  should  be  no  play,  the  armature  might  get  wedged 
between  its  two  bearings  and  cause  hot  boxes  and  stoppage 
of  the  dynamo,  A  swinging  motion  of  the  armature  will 
cause  the  bearing  to  wear  evenly,  distribute  the  oil  from 
end  to  end  of  the  bearings,  and  prevent  heating  of  the 
boxes.  An  armature  can  be  caused  to  play  only  when  the 
dynamo  is  in  proper  alignment  and  the  belt  not  too  tight. 

All  connections  through  which  the  current  ^ias  to  pass 
should  be  cleaned  with  fine  emery  cloth  and  should  not 
touch  any  part  of  the  iron  frame  or  field-coils  of  the 
dynamo. 

CHAPTER  XVI. 
Starting  a  New  Dynamo. 

It  is  advisable  to  run  a  new  dynamo  a  few  hours  or  even 
a  day  without  any  load,  in  order  to  test  the  lubrication, 
etc.,  not  only  of  the  dynamo,  but  of  the  engine,  if  it  should 
be  a  new  one.  If  everything  is  in  good  condition  the  load 
should  be  put  on  gradually.  This  can  be  done,  either  by 
running  the  dynamo  below  normal  speed  and  gradually 
increasing  the  speed,  or  by  using  the  resistance  boxes  and 
starting  with  very  little  current  and  gradually  increas- 
ing^ it. 

The  latter  is  especially  advisable  for  incandescent  lamp 
installations.  The  testing  should  be  made  during  the  day. 
It  will  require  for  small  plants  a  few  hours  ;  for  plants  of 
greater  importance  a  few  days  ;  only  when  everything 
operates  in  good  order  should  the  regular  running  of  the 
installation  commence. 

Every  day  before  starting  the  dynamo,  the  dynamo 
tender  should  examine  the  binding  posts,  commutator  and 
brushes.  If  the  brushes  are  allowed  to  rest  against  the 
commutator,  the  engineer  should  be  careful  not  to  reverse 
the  motion  of  his  engine  when  starting,  as  he  would  spoil 
the  brushes. 

Iron  nails,  bolts  and  small  iron  tools  should  be  kept 
away  from  the  dynamo,  as  they  may  be  attracted  to  the 
machine  and  damage  it. 

Oil  cans  for  filling  the  oil  cups  of  the  dynamo  should  be 
of  non-magnetic  material  (brass  or  zinc). 


DYNAMO  ELECTRIC  MACHINES.          17 

CHAPTER   XVII. 
Keeping  a   Dynamo  in  Good  Order. 

The  dynamo  must  be  kept  scrupulously  clean,  like  any 
other  expensive  machine.  Any  good  engineer  or  dynamo 
tender  will  do  that  without  being  told. 

Copper  dust,  which  will  be  caused  by  the  friction  of  the 
copper  brushes  against  the  commutator,  should  never 
show  ;  it  should  be  cleaned  oft  the  armature  and  fields  by 
means  of  a  paint  brush  and  a  pair  of  bellows  every  day. 
Shafts  and  pulleys  running  near  the  dynamo  must  be  pre- 
vented, by  means  of  shields,  from  throwing  oil  on  the 
dynamo,  especially  on  the  commutator. 

A  brush  sh  mid  never  be  lifted  off  the  commutator  while 
the  dynamo  is  running. 

Binding  posts  and  other  contacts  should  always  be  tight. 
A  slight  vibration  of  the  dynamo,  which  will  occur  even 
when  it  is  properly  set,  will  loosen  these  connections  in 
time.  Every  binding  screw  should  be  examined,  and,  if 
necessary,  tightened  every  day. 

CHAPTER  XVIII. 
Brushes. 

The  setting  of  the  brushes  is  one  of  the  most  important 
duties  of  the  dynamo  tender.  The  brushes  should  rest 
against  the  commutator  with  a  slight  pressure.  They 
should  not  be  rigid,  but  the  brush  holder  springs  should 
allow  a  certain  amount  of  spring  ;  this  will  prevent  exces- 
sive sparking  of  the  brushes,  even  if  the  commutator 
should  be  a  little  uneven. 

The  contact  points  for  the  brushes  on  the  commutator 
are  in  most  dynamos  diametrically  opposite  each  other.  In 
order  to  find  these  points  quickly  it  is  advisable  to  cut  a 
little  strip  of  tin,  the  length  of  which  is  just  one-half  the 
circumference  of  the  commutator,  and  use  this  strip  as  a 
gauge  when  setting  the  brushes.  The  brush  holders 
should  be  carefully  kept  clean,  and  should  be  wiped  off 
every  time  before  the  brushes  are  put  in.  The  brushes 
must  extend  from  each  brush  holder  at  equal  lengths.  The 
insulation  between  the  brush  holder  pins  and  the  quadrant 
must  be  in  good  condition  ;  oil  and  dirt  must  be  kept  out. 


i8 


DYNAMO    TENDERS'  HAND-BOOK. 


Fig.  13  shows  the  proper  positions  of  the  brushes.  The 
point  where  the  brushes  are  resting  on  the  commutator 
when  the  greatest  e.m.f.  is  obtained  are  called  the  neutral 
points,  A,  B.  When  the  brushes  touch  the  points  C,  D. 
at  right  angles  to  A,  B,  no  current  is  obtained. 


FIG.   13.  —  PROPER  POSITION  OF  BRUSHES. 

If  the  brush  is  nearly  worn  through  to  the  middle  of  its 
thickness,  it  should  be  turned  over  and  the  other  side  used 


pIG    I4. —  WORN  BRUSH  AND  BLOCKS  FOR  TRIMMING, 

on  the  commutator.  When  both  sides  are  worn  off,  as 
shown  in  the  upper  patt  of  Fig.  14,  the  brushes  should  be 
trimmed.  In  larger  stations,  little  brush  cutting  machines 
are  used  f}r  this  purpose  ;  in  smaller  installations,  two 


DYNAMO  ELECTRIC  MACHINES.          19 

blocks  of  hard  wood,  lower  part  of  Fig.  14,  are  used.  The 
brush  is  put  between  the  two  blocks  and  the  whole  put  in  a 
vise.  The  end  of  the  brush  projecting  beyond  the  wooden 
blocks  is  then  removed  by  means  of  a  file. 

The  brushes  should  also  be  in  such  a  position  on  the 
commutator  that  the  least  sparking  will  be  set  up.  In 
some  dynamos  it  is  necessary  to  move  the  brushes  in  pro- 
portion to  the  load  in  order  to  get  little  sparking.  In 
other  systems,  the  brushes  need  not  be  moved  at  all,  no 
matter  how  many  lights  are  turned  on  or  off.  In  some 
dynamos,  the  moving  of  the  quadrant,  or,  in  other  words, 
the  moving  of  the  contact  points  of  the  brushes  on  the 
commutator,  is  used  for  increasing  or  decreasing  the 
strength  of  the  current. 

CHAPTER    XIX. 
The  Commutator. 

The  commutator  is  the  most  sensitive  part  of  ihe  dynamo, 
and  should  be  especially  cared  for.  It  must  always  be 
kept  smooth.  If  it  should  get  rough  from  the  electric 
spark,  it  is  necessary  to  smooth  it  by  pressing  a  block  of 
wood  covered  with  fine  emery  cloth  against  it,  after  having 
set  the  dynamo  in  motion  with  the  brushes  lifted  off.  If 
the  commutator  is  so  rough  that  a  smooth  surface  cannot 
be  obtained  by  the  use  of  emery  cloth,  it  should  be  filed. 
In  order  to  do  that,  it  is  necessary  to  take  out  the  brush 
holders,  pins  and  brushes.  After  a  straight  surface  has 
been  obtained,  the  commutator  should  be  smoothed  with 
fine  emery  cloth. 

The  disadvantages  of  using  a  file  on  a  commutator  are  the 
liability  of  pressing  small  chips  of  copper  into  the  insula- 
tion between  the  copper  segments,  and  the  impossibility  of 
getting  the  commutator  true.  The  best  way  is  to  turn 
The  commutator  off  by  means  of  a  little  lathe,  which  can  be 
attached  to  the  dynamo,  or  by  taking  the  armature  out  of 
the  dynamo  and  having  the  commutator  turned  off  in  a 
lathe  in  a  machine  shop.  This  will  not  only  make  the 
commutator  smooth  but  perfectly  true.  In  filing  or  turn- 
ing off  the  commutator  while  the  armature  is  rotating  in  the 
dynamo,  it  is  necessary  to  reduce  the  normal  speed  of  the 
dynamo  considerably,  as  too  high  a  speed  would  spoil  com- 
mutator and  turning  tools. 

In  new  commutators  for  which  fiber  is  used  as  insulation 
between  the  copper  segments,  it  is  very  often  found  that 


20        DYNAMO    TENDERS'  HAND-BOOK. 

the  thin  sheets  of  fiber  have  absorbed  moisture,  and  extend 
above  the  surface  of  the  commutator.  If  a  few  days'  ex- 
posure in  a  dry  warm  room  does  not  cause  the  fiber  to 
shrink  and  go  back  to  its  place,  the  surface  of  the  commu- 
tator must  be  smoothed  first  with  coarse  and  then  with 
fine  emery  cloth. 

In  most  systems  it  is  advisable  to  put  a  little  oil  on  the 
commutator  just  after  starting  the  dynamo.  Very  little  oil, 
however,  must  be  used.  Dip  the  point  of  one  finger  in  one 
drop  of  oil,  distribute  it  by  rubbing  it  on  the  inner  surface 
of  the  hand  and  apply  what  oil  remains  on  the  finger  tip  to 
the  commutator,  and  take  it  off  with  another  finger.  This 
will  do  for  at  least  three  hours'  run. 

If  it  should  become  necessary  at  any  time  to  replace  the 
commutator  by  a  new  one,  it  should  be  done  in  the  follow- 
ing manner :  Take  the  armature  out  of  the  dynamo  and 
put  the  two  ends  of  the  shaft  on  two  wooden  horses. 
Mark  the  wires  leading  from  the  armature  to  the  commu- 
tator by  attaching  little  tags  with  numbers,  to  make  sure 
of  the  proper  place  of  each  wire  after  taking  off  the  commu- 
tator. Then  disconnect  these  wires  from  the  correspond- 
ing copper  bars  of  the  commutator,  either  by  unscrewing 
the  set  screw,  or  in  commutators  which  have  solid  connec- 
tions, by  unsoldering  them  by  means  of  a  hot  soldering 
iron.  Take  the  commutator  off,  clean  the  shaft  and  con- 
nections and  put  the  new  commutator  carefully  in  its 
proper  position  and  connect  the  wires  in  proper  turn  to  the 
corresponding  copper  bars  of  the  commutator  by  means  of 
set  screws,  or  soldering  with  hard  solder.  The  greatest 
care  must  be  observed  not  to  short-circuit  any  parts  of  the 
commutator  with  drops  of  molten  solder. 

CHAPTER    XX. 
Repairs. 

A,  to  the  Armature. — In  most  cases  repairs  to  the  arma- 
ture are  necessitated  by  injuries  to  the  insulation  of  the 
wire  from  external  mechanical  sources  or  by  excessive 
heat  generated  in  the  armature.  The  first  is  very  often 
caused  by  little  particles  of  material  dropping  in  the  spaces 
between  armature  and  pole  pieces— for  instance,  little  balls 
of  cotton  waste  being  caught  from  the  end  of  the  dynarnjD 
and  pressed  between  armature  and  pole  pieces,  thus  scaling 
off  the  insulation  of  the  wires  in  some  places,  or  bursting 
the  metal  bands.  Such  injuries  can  have  two  different  re- 


DYNAMO  ELECTRIC  MACHINES.          21 

suits, '  either  short  circuiting  some  of  the  coils  or  bringing 
different  parts  of  the  wire  coils  in  contact  with  the  iron 
core.  These  injuries  hardly  ever  extend  below  the  first 
layer  of  wire.  In  most  cases  it  wilt  be  possible  to  care- 
fully lift  one  wire  at  a  time  just  high  enough  to  wrap  it 
with  silk  tape,  and  thus  insulate  it.  After  having  wrapped 
and  insulated  all  the  injured  parts,  drive  the  wires  back 
into  their  position  by  means  of  a  small  hard  wood  block 
and  hammer,  and  give  them  two  or  three  good  coatings  of 
shellac  varnish.  If  the  injuries  are  below  the  first  layer  of 
the  armature,  it  will  be  necessary  in  most  cases  to  have  it 
sent  to  the  factory  to  be  re-wound.  . 

Excessive  heat  in  the  armature  will  very  often  char  the 
insulation  of  one  or  more  coils  of  wire  entirely.  These 
coils,  of  course,  must  be  taken  out  and  replaced  with  new 
wire.  In  most  armatures  of  the  so-called  Gramme  pattern 
this  can  be  easily  done.  In  armatures  of  the  Siemens  drum 
pattern  it  will  necessitate  a  re-winding  of  the  whole  arma- 
ture. The  over-heating  of  one  or  more  coils  of  an  armature 
is  very  often  caused  by  the  short-circuiting  of  two  or  more 
segments  of  the  commutator  by  means  of  copper  dust 
which  has  been  allowed  to  settle  back  of  the  commutator, 
or  by  excessive  sparking  of  the  brushes,  forming  little 
bridges  of  metal  across  to  adjacent  commutator  segments. 

B,  to  the  Field  Magnets. — The  faults  which  mostly  occur 
in  field  magnets  consist  in  short-circuiting  coils,  or  in  get- 
ting parts  of  the  field  wire  in  contact  with  the  iron  core. 
The  field  wire  should  be  unwound  until  the  damaged  part 
is  reached,  and  after  insulating  it  properly  as  described  be- 
fore, it  should  be  wound  back  on  the  core.  If  it  should  be 
necessary  to  take  a  considerable  amount  of  wire  off  the 
field  in  this  way  it  will  be  advisable  to  put  the  damaged 
field  magnet  in  a  lathe  and  do  the  unwinding  and  pe-wind- 
ing  by  means  of  the  lathe. 

CHAPTER    XXI. 

Testing  the  Wire  Coils  of  a  Dynamo  for 
Contact  Against  Iron. 

The  iron  frame  of  each  dynamo  must  be  well  insulated 
from  the  wire  coils  of  the  field,  the  armature  and  also  from 
any  connection  with  the  earth.  If  one  of  these  wire  coils 
should  get  in  contact  with  the  iron  frame  of  the  dynamo 
and  the  latter  should  be  in  connection  with  the  earth  by 
means  of  foundation  bolts,  etc.,  it  would  cause  what  is 


2?,         D  YNAMO    TENDERS'  HAND-BOOK. 

called  a  ground.  This  ground  must  be  considered  the 
worst  enemy  of  electric  light  apparatus,  and  should  never 
be  allowed  to  exist.  We  have  shown  how  to  test  for 
grounds  in  Chapter  VI.  The  same  method  can  be  applied 
in  testing  for  contact  between  field  wire  coils  or  armature 
coils  and  the  iron.  During  the  test,  any  wires  leading  to 
the  circuits  or  other  apparatus  should  be  disconnected  from 
the  dynamo  in  order  to  make  sure  that  the  fault  really  lies  in 
the  dynamo  itself.  Another  fault  sometimes  found  in  the 
field  of  the  armature  is  called  a  short  circuit. 

A  short  circuit  is  a  shunt  of  little  resistance  between  two 
points  of  a  conductor.  Suppose  the  points  A  and  B,  in 
Fig.  15,  are  set  in  some  way  in  connection.  It  is  clear  that 
the  main  part  of  the  current  will  pass  through  A,  B,  and 
but  very  little  current  will  pass  through  the  coil.  If  this 
should  occur  in  the  armature,  the  coil  thus  short-circuited 
in  itself  will  generate  currents  of  great  strength,  whicli  will 
destroy  the  insulation  of  this 
coil  in  a  very  short  time. 
Generally  the  dynamo  tender 
will  be  warned  by  a  smell  of 
burnt  cotton  and  shellac.  If 
this  fault  should  occur  in  a 
field  magnet  it  would  de- 
crease its  power,  and  thus 
cause  the  different  magnets 
of  the  field  to  be  of  unequal  FIG.  15 — A  SHORT  CIRCUIT. 
strength.  It  may  cause 

heating  of  the  field  in  shunt  and  compound  dynamos, 
while  in  series  dynamos  it  will  simply  decrease  the 
current  strength  generated  by  the  dynamo.  In  order 
to  test  for  a  short  circuit  in  an  armature  coil,  or  a  field 
magnet,  it  is  necessary  to  disconnect  each  field  coil,  or 
each  armature  coil,  and  measure  by  proper  instruments  the 
resistance  of  each  coil.  If  any  magnet  coil  shows  a  resist- 
ance below  the  others,  it  is  short-circuited.  The  use  of  the 
necessary  testing  apparatus  ca  i  not  be  described  here,  as  it 
would  go  beyond  the  limits  of  this  little  book. 

The  short  circuits  in  field  coils,  however,  can  very  often 
be  found  without  the  use  of  finer  testing  instruments, 
simply  by  the  use  of  the  detector  galvanometer  and  the 
cell.  By  connecting  each  field  coil  in  series  with  galvanom- 
eter and  ceU,  and  marking  the  deflection  of  the  galvanom- 
eter, the  coil  which  will  show  the  greatest  deflection  is  the 
one  which  is  short-circuited.  A  short-circuited  field  mag- 


mm 

^ 


DYNAMO  ELECTRIC  MACHINES.          23 

net  will  heat  less  than  a  sound  magnet  when  the  dynamo  is 
generating  current.  A  break  of  the  field  wire  can  very 
easily  be  found  by  means  of  the  galvanometer,  as  no  deflec- 
tion would  be  obtained  at  all  through  the  broken  coil.  A 
break  in  a  wir.e  coil  of  the  armature  could  only  be  found  by 
disconnecting  all  wire  coils  from  the  commutator  and  from 
each  other,  and  then  testing  each  coil  separately  in  the 
manner  described.  This,  however,  would  involve  consid- 
erable work  and  delay,  and  a  quicker  method  may  be  em- 
ployed :  Set  the  dynamo  in  operation  ;  then  take  a  short 
piece  of  wire  and  touch  the  commutator  with  the  two  ends 
of  this  wire  at  a  distance  of  three  or  four  segments  apart, 


FIG.  16. — TESTING  FOR   A   BREAK   IN  AN   ARMATURE 
COIL. 

Fig.  16.  If  the  machine  should  commence  to  generate 
current,  an  electric  arc  will  be  formed  on  the  commutator 
between  the  two  ends  of  this  wire,  and  indicate  there  is  a 
break  in  the  armature  wire.  The  machine  must  be  shut 
down  quickly,  as  otherwise  it  would  cause  damage  in 
the  commutator  and  armature.  The  coil  of  the  armature 
in  which  the  fault  lies  can  be  easily  recognized  by  the  burns 
on  the  corresponding  segments  of  the  commutator.  Faults 
of  this  kind  are  very  often  found  in  poor  contacts  between 
two  coils,  or  between  a  coil  and  the  corresponding  copper 


*4        DYNAMO    TENDERS'  HAND-BOOK. 

bar  of  the  commutator.  Poor  contacts  will  cause  more 
trouble  than  actual  breakage  of  the  wire.  Such  faults  will 
often  destroy  certain  commutator  segments,  caused  by 
increased  sparking  of  the  brushes  when  passing  these 
points.  Hence,  if  only  one  or  two  commutator  segments 
should  show  rapid  destruction  from  the  electric  spark,  all 
the  connections  between  these  segments  to  the  correspond- 
ing armature  coils  should  be  well  examined,  and,  if  neces- 
sary, cleaned  and  well  tightened,  or  made  solid  with  solder. 
The  poor  contact  between  parts  of  the  field  wire  coils  can 
be  very  often  discovered  by  holding  a  piece  of  iron,  for 
instance  a  machine  wrench,  near  the  pole  piece  without 
touching  it.  If  the  contacts  are  good  the  wrench  will  be 
attracted  with  a  uniform  force;  if  poor,  these  forces  will 
vary  and  cause  a  singular  vibratory  motion  of  the  wrench 
in  the  hand. 


DISEASES   OF   DYNAMOS. 


CHAPTER  XXII. 

Non  -  generation   of  Current  by  the 
Dynamo. 

There  may  be  numerous  causes  for  such  an  occurrence. 

First,  the  residual  magnetism  in  the  field  magnets  of  the 
dynamo  may  be  too  weak.  Series  dynamos  can  be  started  in 
such  a  case  when  running  at  normal  speed,  by  short  circuit' 
ing  the  two  binding  posts  with  a  piece  of  wire  for  a  frac- 
tion of  a  second  ;  if  short-circuited  too  long,  serious 
damage  may  be  dpne  to  the  commutator.  This  operation 
can  not  be  applied  to  shunt  dynamos,  as  they  will  not  gen- 
erate any  current  when  the  binding  posts  of  the  machine 
or  the  outgoing  wires  are  short-circuited.  In  order  to  start 
shunt  dynamos,  the  external  circuit  must  be  disconnected 
from  the  dynamo,  and,  after  the  dynamo  has  been  running 
at  normal  speed  for  about  a  minute,  the  external  circuit 
must  be  suddenly  thrown  on  the  dynamo. 

Secondly,  poor  contacts  may  be  the  cause.  Every  con- 
nection of  the  armature  and  the  magnets  should  be  closely 
inspected.  If  necessary  the  contacts  should  be  cleaned  and 
set  screws  tightened. 

Thirdly,  the  insulation  of  the  binding  posts  and  the 
brush  holders  may  be  in  poor  condition.  For  instance,  if 
the  metal  bars  of  the  brush  holders  should  touch  the  quad- 
rant, the  armature  would  be  short-circuited  and  no  current 
would  be  generated.  Such  faults  can  be  very  easily* de- 
tected by  means  of  the  detector  galvanometer,  as  described 
in  Chapter  VI. 

Fourthly,  if  one  or  more  field  magnets  are  short-circuited 
the  dyoamo  will  generate  current,  but  the  current  will  not 
be  at  normal  strength.  In  this  case  the  dynamo  should  be 
examined,  as  described  in  Chapter  XXI. 

Fifthly,  shunt  dynamos,  as  mentioned  heretofore,  will 
not  generate  any  current  when  short-circuited.  This  is 
especially  true  for  small  dynamos.  In  incandescent  lamp 
installations,  for  instance,  it  may  happen  that  two  branch 
wires  or  two  contact  points  in  a  lamp-holder,  are  short- 

25 


26        DYNAMO    TENDERS'  HAND-BOOK. 

circuited.  Even  as  trivial  a  fault  as  this  may  be  sufficient 
to  prevent  the  dynamo  from  generating  any  current  at  all. 
By  taking  out  one  of  the  circuit  wires  and  putting  an  incan- 
descent lamp  between  the  binding  posts  of  the  dynamo,  it 
can  be  very  easily  discovered  whether  the  fault  is  in  the 
dynamo  or  in  the  external  circuit.  If  the  lamp  burns  prop- 
erly, the  fault  is  in  the  circuit.  If  it  does  not  burn  properly, 
the  fault  is  in  the  dynamo.  If  the  fault  should  be  in  the 
circuit,  insert  the  circuit  wire  suddenly  in  the  binding 
post,  and  the  short  circuit  will  show  either  by  burning  out 
or  by  fusing  a  safety  plug.  Great  care  should  be  taken  in 
making  this  test  not  to  set  the  building  on  fire,  as  consider- 
able sparking  and  often  melting  of  a  small  wire  may  be 
caused  in  the  place  where  the  short  circuit  is.  If  the  short 
circuit  should  be  heavy,  the  probability  is  that  the  belt  will 
fly  off  the  dynamo  pulley.  In  such  a  case  the  short  circuit 
must  be  located  by  means  of  the  detector  galvanometer.  It 
is  advisable  to  watch  the  belt  before  inserting  the  wire  in 
the  binding  post,  in  order  that  it  may  not  be  injured  by 
being  thrown  off.  If  the  belt  on  the  dynamo  pulley  com- 
mences to  squeak  and  the  lamp  between  the  binding  posts 
commences  to  burn  dimly,  the  wire  should  be  pulled  quickly 
back  again,  and  this  operation  not  carried  any  further,  but 
the  fault  should  be  located  by  means  of  the  galvanometer. 


CHAPTER  XXIII. 

Excessive  Sparking  of  Commutator  and 
Brushes, 

The  causes  for  excessive  sparking  of  commutator  and 
brushes  may  be  classified  as  follows : 

First,  poor  condition  of  the  brushes  and  brush  holders. 

Secondly p,  faulty  adjustment  of  the  brushes  [See  Chapters 
XVIII  and  XIX]. 

Thirdly,  the  surface  of  the  commutator  may  be  rough  or 
covered  with  dirt  and  grease  [See  Chapter  XIX]. 

Fourthly,  the  insulation  of  one  field  magnet  coil  may  be 
injured  and  the  coil  short-circuited  in  itself.  If  one  magnet 
is  more  excited  than  the  other,  one  brush  will  spark  more 
than  the  opposite  one,  in  the  same  way  as  if  the  brushes 
were  not  properly  adjusted. 

Fifthly,  two  or  more  segments  of  the  commutator  may 
be  short-circuited. 


DISEASES   OF  DYNAMOS.  37 

Sixthly  t  the  dynamo  may  be  overloaded.  This  will  cause 
not  only  an  excessive  sparking  of  the  brushes  but  a  consid- 
erable heating  of  the  armature  and  fields.  The  overloading 
of  the  dynamo  may  be  caused  by  poor  insulation  of  the  ex- 
ternal  circuit,  thus  causing  a  considerable  amount  of  current 
to  escape  from  one  pole  to  the  other.  Grounding  of  the 
external  wires,  which  frequently  happens  in  rainy  weather,, 
will  bring  about  the  same  result. 

In  arc  lighting,  lamps  may  be  fed  by  too  strong  a  current, 
or  in  incandescent  lighting,  too  many  lamps  may  be  put  on 
the  leads. 


LAMPS. 

CHAPTER  XXIV. 
Arc  Lamps. 

When  an  electric  current  has  passed  through  two  carbon 
pencils  in  contact  with  each  other  and  then  separated,  an 
electric  spark  will  jump  through  the  short  space  between 
the  two  carbons  and  produce  what  is  called  the  electric  arc. 
In  continuous  current  systems  the  positive  carbon  will  be- 
come more  incandescent  than  the  negative  and  burn  about 
twice  as  fast.  When  an  alternating  current  is  used  the  two 
carbons  will  become  equally  incandescent  and  will  be  con- 
sumed at  about  equal  rates. 

In  continuous  current  machines  the  arc  lamps  are 
so  arranged  that  the  upper  carbon  must  be  the  positive, 
and  the  lower  carbon  the  negative.  The  upper  carbon  will 
form  a  little  crater  and  reflect  the  light  downward, 
Fig.  17.  It  is  very  important  to  have  the  distance  between 
the  two  carbons  kept  uniform  at  all  times,  in  order  to  have 
the  lamps  burn  steadily.  The  lengths  of  the  arcs  of  the 
different  systems  vary  from  ^  to  *£  of  an  inch.  By  the 
use  of  dark  glasses  one  can  observe  the  arc  without  injuring 
the  sight.  Systems  using  the  short  arc  are  very  often  said  to 
employ  low  tension,  while  systems  using  a  long  arc  are 
said  to  employ  high  tension. 

Arc  lamps  with  a  shoit  arc  use  a  current  from  1 8  to  25 
amperes,  and  an  e.  m.  f.  of  from  25  to  35  volts,  while  arc 
lamps  with  a  long  arc  use  a  current  of  from  7  to  12  am- 
peres, and  an  e.  m.  f.  from  40  to  60  volts.  The  feeding 
mechanism  of  an  arc  lamp  must  keep  the  arc  at  a  uniform 
length  and  allow  the  positive  carbon  to  feed  down  at  the 
proper  rate.  Lamps  in  which  both  carbons  are  feeding 
towards  the  arc  are  called  focussing  lamps,  and  are  made 
for  the  purpose  of  keeping  the  arc  in  one  spot,  so  a  pro- 
jector may  be  used  to  advantage. 

If  more  than  one  lamp  is  to  run  from  one  dynamo  a 
shunt  must  be  provided  in  the  lamp,  Fig.  18.  These 
lamps  are  generally  called  differential  lamps,  as  the  differ- 
ence between  the  current  strength  passing  throughout  the 


LAMPS.  29 

coarse  wire  coil  Slf  and  the  current  strength  passing 
through  the  fine  wire  coil,  S2,  operates  the  feeding  mechan- 
ism. An  arc  lamp  which  is  to  be  run  alone  from  one  dy- 
namo has  only  the  coarse  wire  coil.  The  current  passes 
from  the  positive  binding  post  through  the  coil,  thence 
through  a  contact  to  the  upper  carbon,  then  passes  through 
the  lower  carbon  and  out  to  the  negative  binding  post. 


FIG.  17.  — ARC  LIGHT  CARBONS. 

The  iron  armature  or  core  which  is  connected  with  the 
upper  carbon  holder  regulates  the  arc  according  to  the  in- 
crease or  decrease  of  the  current  strength.  If  the  arc 
elongates  too  much  the  current  strength  in  the  coil  will  de- 
crease, and  allow  the  iron  core  to  drop.  On  the  other 
hand,  if  the  length  of  the  arc  should  be  too  short  the  cur- 


30        DYNAMO    TENDERS'   HAND-BOOK. 

rent  strength  in  the  coil  will  increase  and  lift  the  iron  core, 
thus  increasing  the  length  of  the  arc.  Fig.  1 8  illustrates 
a  differential  lamp  as  used  when  a  series  of  lamps  are  run 
from  one  dynamo.  The  lamp  has,  as  described  heretofore, 
in  shunt  with  the  two  binding  posts,  a  fine  wire  coil  which 
helps  to  regulate  in  the  following  manner :  The  current 
through  the  circuit  must  be  kept  at  a  uniform  strength  ;  if 
there  was  no  shunt  coil  an  increase  of  the  arc  of  one  lamp 
would  decrease  the  current  strength  through  the  whole  cir- 
cuit and  make  the  other  lamps  dim.  This  would  cause  a 
permanent  fluttering  of  the  arcs  and  no  steady  light  could 
be  obtained.  In  using  a  shunt  coil  each  lamp  is  made 
practically  independent  of  the  other  lamps  in  the  same  cir- 
cuit. If  the  arc  should  elongate,  the  flow  of  the  current 
through  the  coarse  wire  coil  will  decrease,  but  at  the  sime 


FIG.  18. —  SHUNT  FOR  ARC  LAMPS. 

cime  will  increase  through  the  shunt  coil.  This  will  prac- 
tically keep  the  current  strength  passing  from  the  positive 
to  the  negative  binding  post  of  the  lamp  uniform  ;  at  the 
same  time  a  decrease  of  the  strength  of  the  coarse  wire 
coil  and  a  strengthening  of  the  fine  wire  coil  will  pull  down 
the  upper  carbon  holder  and  regulate  the  arc  to  its  proper 
length.  Each  system,  of  course,  will  necessarily  require 
certain  special  instructions  which  cannot  be  given  here. 

Arc  lamps  are  generally  connected  in  series,  as  shown  in 
Fig.  19.  The  positive  binding  post  of  the  dynamo  con- 
nects to  the  positive  binding  post  of  the  first  lamp,  the 
negative  binding  post  of  the  first  lamp  to  the  positive  bind- 
ing post  of  the  second  lamp,  and  so  on  until  finally  the 


LAMPS.  & 

negative  binding  post  of  the  last  lamp  connects  to  the  nega- 
tive binding  pest  of  the  dynamo. 

An  ammeter  should  be  connected  in  the  circuit  to  show 
at  all  times  the  current  strength,  which  must  be  kept  con- 
stant in  such  a  system.  The  e.  m.  f.  between  the  binding 
post  of  the  dynamo  will  depend  upon  the  e.  m.  f.  of  each 
lamp,  and  the  number  of  lamps  in  the  circuit.  If,  for  in- 
stance, one  lamp  requires  50  volts,  and  there  are  ten  lamps 
in  the  circuit  the  total  e.  m.  f.  between  the  binding  posts  of 
the  dynamo  would  amount  to  50  x  10=500  volts.  Besides 
the  ammeter  there  is  generally  a  hand  or  automatic  regula- 
tor connected  in  the  circuit  to  enable  the  dynamo  tender  to 
keep  a  constant  current  strength  in  the  circuit.  If  one  or 
more  lamps  should  be  turned  out,  the  current  strength 
would  increase  if  properly  arranged  devices  did  not  cut 

_ i* 

'  + 


i 

-t — ^ 

FIG.  19. — ARC  LAMPS  IN  SERIES. 

down  the  e.  m.  f.  cf  the  machine,  and  thus  keep  the  cur- 
rent strength  at  its  normal. 

CHAPTER    XXV. 
Suspension  of  Arc  Lamps. 

Arc  lamps  should  be  securely. fastened  and  properly  in- 
sulated from  the  point  of  suspension.  When  used  outdoors 
a  weather-hood  should  be  put  above  the  lamp  to  protect  it 
from  rain  or  snow.  The  wires  leading  to  the  lamp  should 
be  well  insulated  in  order  to  prevent  their  getting  in  con- 
tact with  any  part  of  the  lamp,  except  the  binding  posts. 
The  set  screws  of  the  binding  post  should  be  well  tightened. 

If  cords  and  pulleys,  or  counterpoises  and  flexible  cables 
are  used  for  raising  and  lowering  lamps  it  is  well  to  ex- 
amine all  these  parts  carefully  every  few  months,  as  ropes 
and  flexible  cables  will  wear  out,  and  the  lamps  or  counter- 
poises may  drop,  and  bring  property  and  human  life  in 
danger.  For  these  reasons  it  is  preferable  to  have  the 
lamps  put  up  stationary,  or  devices  should  be  used  which 
will  take  the  strain  off  the  ropes  or  cables  when  the  lamp  is 
in  its  place. 


32         DYNAMO    TENDERS'  HAND-BOOK. 

CHAPTER  XXVI. 
Trimming  and  Cleaning  Arc  Lamps. 

Special  instructions  are  given  for  each  system  when  the 
plant  is  put  in  operation.  The  following,  however,  are 
general  rules  which  will  apply  to  all  systems  :  In  putting 
in  the  carbons  care  should  be  taken  that  they  are  well 
pointed,  and  that  they  are  not  too  long.  There  should  be 
sufficient  space  to  allow  the  feeding  mechanism  to  separate 
the  carbons  at  least  one-fourth  of  an  inch.  The  carbon 
holders  and  all  other  parts  of  the  lamp  which  are  exposed 
should  be  dusted  off  every  time  before  putting  in  new  car- 
bons. The  carbon  rods  should  be  cleaned  with  a  clean  rag 
moistened  with  benzine  or  spirits  of  ammonia  every  day. 
Contact  points  and  binding  screws  are  to  be  kept  clean  and 
well  tightened.  The  upper  carbon,  as  has  been  described, 
will  be  consumed  about  twice  as  fast  as  the  lowrer  one  ; 
hence  the  upper  carbon  should  be  twice  as  long  as  the 
lower  carbon.  Generally  the  upper  carbon  is  made  12 
inches  long,  and  the  lower  carbon  6  inches  long.  One  set 
of  carbons  will  last  from  5  to  8  hours  according  to  the  cur- 
rent and  kind  of  carbons  used.  Larger  carbons  will  burn 
longer  than  carbons  of  smaller  diameter  ;  but  generally 
lamp's  will  burn  more  steadily  with  carbons  of  smaller 
diameter  than  with  those  of  larger  diameter.  Short-arc 
lamps  use  mostly  carbons  from  seven-sixteenths  to  one-half 
inch  diameter,  while  long-arc  lamps  use  carbons  from 
three-eighths  to  seven-sixteenths  inch  diameter.  Carbons 
should  be  kept  in  a  dry  place. 

CHAPTER  XXVII. 
Incandescent  or  Glow  Lamps. 

An  incandescent  lamp  consists  of  a  carbon  filament 
inclosed  in  a  glass  globe  from  which  the  air  has  been 
exhausted  by  means  of  an  air  pump.  The  electric  current 
passes  through  the  carbon  filament,  which  offers  so  much 
resistance  that  it  becomes  very  hot  and  glows,  or,  as  we 
say,  becomes  incandescent.  Most  incandescent  lamps  are 
made  for  an  e.m.f.  of  from  50  to  120  volts.  Lamps  should 
always  be  burned  at  the  proper  e.m  f.  If  they  run  above 
the  normal  e.m.f.,  the  candle  power  will  be  increased,  but 
the  life  of  the  lamp  will  be  very  much  shortened.  Incandes- 


LAMPS.  33 

cent  lamps  can  be  connected  to  the  dynamo  in  various 
ways;  for  isolated  plants  they  are  generally  connected  in 
parallel  or  multiple  arc 

CHAPTER  XXVIII. 
Multiple  Arc  System. 

Fig.  20  shows  the  method  of  connecting  lamps  to  the 
dynamo  in  multiple  arc.  Each  lamp  is  independent,  and 
any  number  of  lamps  can  be  switched  in  or  out  without 
interfering  with  the  other  lamps,  provided  the  e.m.f.  be- 
tween the  parallel  mains  is  kept  constant.  Generally  lamps 
of  the  same  e.m.f.  are  connected  in  the  same  system,  but 


FIG.  20.  —  LAMPS  IN  MULTIPLE  ARC. 

if,  for  instance,  we  should  want  to  use  50  volt  and  100  volt 
lamps  in  the  same  system,  we  would  connect  the  loo  volt 
lamps  direct  between  the  mains,  as  shown  in  the  drawing; 
with  A,  and  the  50  volt  lamps  in  series  of  two.  with  B, 
The  two  lamps  marked  B,  of  course,  are  not  independent, 
if  one  should  break  or  be  switched  out,  the  other  lamps 
would  go  out  also. 

CHAPTER  XXIX. 
Multiple  Series  System. 

In  some  cases  it  is  necessary  to  use  dynamos  of  a  higher 
e.m.t.  for  incandescent  lighting,  and  in  such  cases  the 
lamps  are  connected  between  the  two  mains  in  series, 
Fig.  21.  If,  for  instance,  the  electromotive  force  of  the 
dynamo  is  500  volts,  and  100  volt  lamps  should  be  used, 
five  lamps  would  have  to  be  connected  in  series  in  order  to 


34 


DYNAMO    TENDERS'  HAND-BOOK. 


divide  the  e.m.f.  properly.  In  this  system,  of  course,  if 
one  lamp  in  one  series  should  break,  the  other  lamps  of 
this  series  would  go  out  also.  This  has  been  practically 


FIG.  21.  —  LAMPS  IN  MULTIPLE  SERIES. 

avoided  by  providing  each  lamp,  Fig.  22,  with  a  little  cut 
out  and  connecting  in  the  circuit  an  extra  lamp  or  a  resst- 
ance  coil.  If  one  lamp  should  break  or  be  switched  out, 
the  cut-out  will  switch  into  its  place  an  equal  resistance. 
This  arrangement  will  prevent  any  other  lamp  in  the  series 
from  going  out,  and  sustain  the  same  current  strength 
through  the  whole  series  at  all  times.  The  device  is 
explained  by  Fig.  23,  in  which  M  is  the  magnet,  A  arma- 
ture, R  resistance  equal  to  lamp,  C  contact,  and  L  lamp. 

The  current  generated  by  the  dynamo  in  the  multiple 
series  system  will  be  in  proportion  to  the  number  of  series 
burning.  The  more  series  switched  in,  the  more  current 
will  be  required.  In  this  system,  as  well  as  in  the  multiple 
arc  system,  a  constant  e.m.f.  is  required  in  the  main  wires, 


LAMPS. 


35 


while  the  current  strength  will  vary  in  proportion  to  the 

number  of  lamps  or  number  of  series. 

\  In  the  multiple  series  sys- 

tem, of  course  the  switching 
out  of  one  or  more  lamps  in 
a  group  will  not  result  in 
any  saving  in  the  power  of 
the  engine  or  waterwheel;  a 
saving  is  effected  only  by 
switching  out  one  whole  se- 
ries or  more  at  a  time.  This 
is  a  disadvantage  in  compar- 
ison with  the  multiple  arc 
system,  in  which  the  switch- 
ing out  of  one  lamp  means  a 
proportional  reduction  in 
the  power  needed  to  run  the 
dynamo. 

A  little  saving  in  power  is 
of  no  consequence  where  fuel 
is  cheap  or  a  waterwheel 
is  used. 


FIG.  22.  —  LAMP  IN 
MULTIPLE  SERIES. 

In  larger  stores,  or 
places  of  amusement, 
where  all  the  lights 
are  required  at  one 
time  the  multiple  se- 
ries system  in  regard 
to  saving  of  power 
stands  on  an  equal 
footing  with  the  mul- 
tiple arc  system. 


FIG.  23.  —  CUT- 
OUT  FOR  LAMP 
IN  MULTIPLE 
SERIES, 


3c        DYNAMO    TENDERS'   HAND-BOOK. 

CHAPTER  XXX. 
Series  Multiple  System. 

In  this  system  the  current  strength  of  the  dynamo  must 
be  constant,  and  the  number  of  lamps  for  each  group  will 
depend  upon  the  current  strength  generated  by  the  dynamo 
and  the  current  strength  required  for  each  lamp, 
Fig.  24.  For  instance,  the  current  of  the  dynamo  is  10 
amperes,  and  each  lamp  requires  2  amperes  ;  5  lamps  would 
be  connected  in  each  group,  to  divide  the  current  properly 
and  give  each  lamp  its  share.  Of  course,  instead  of  2 


-o- 
-o 
-o- 
-o- 
-o- 

FIG.  24.  —  LAMPS  IN  SERIES  MULTIPLE. 

lamps  of  2  amperes,  I  lamp  of  4  amperes,  or  4  lamps  of  I 
ampere,  could  be  used. 

All  the  lamps,  however,  in  one  group  must  be  of  the 
same  e.  m.  f.  In  this  system  the  e.  m.  f.  of  the  dynamo 
must  be  varied  in  proportion  to  the  number  of  series  burn- 
ing in  a  similar  way  as  in  an  arc  light  circuit.  In  fact,  in 
in  this  sense  each  group  of  lamps  can  be  considered  as  an 
arc  lamp,  and  this  is  the  reason  that  persons  engaged  in 
the  electric  light  business  very  often  speak  of  incandescent 
lamps  running  on  arc  light  wires,  simply  meaning  that  the 
lamps  are  connected  in  series  multiple,  as  explained. 


CHAPTER   XXXI. 

Arc  and   Incandescent  Lamps  on  the 
Same   Circuit, 

It  can  be  easily  seen  that  in  place  of  a  group  of  incan- 
descent lamps  in  the  series  multiple  system,  as  described, 


LAMPS.  37 

an  arc  lamp  may  be  inserted,  Fig.  25.  Such  a  combina- 
tion, however,  is  neither  advisable  nor  practical  as  the 
fluctuations  of  the  arc  lamps  will  show  in  the  incandescent 
lamps. 

In  this  system,  as  well  as  in  the  series  multiple  system, 
a  similar  disadvantage  to  that  described  in  Chapter  XXIX, 
will  occur  if  one  of  the  lamps  should  break.  The  lamps, 


FIG.  25. — ARC  AND  INCANDESCENT  LAMPS  ON  THE 

SAME  CIRCUIT. 

of  course,  wilt  not  go  out,  but  if  one  lamp  should  break,, 
the  remainder  of  the  lamps  in  the  same  group  will  brighten 
up  considerably  and  thus  injure  the  life  of  the  lamps.  If 
not  discovered  in  time,  more  lamps  may  break  and  finally 
the  whole  series  may  go  out  and  break  the  circuit  entirely. 
The  breakage  of  the  last  lamp  in  the  series  might  cause 


33         DYNAMO    TENDERS'  HAND-BOOK. 

considerable  "damage  to  property,  as  owing  to  the  high  e. 
m.  f.  of  the  dynamo,  a  considerable  arc  may  be  set  up 
which  may  destroy  the  lamp  fixtures  and  set  fire  to  the 
building.  The  disadvantage  can  be  overcome  by  the  same 
cut-outs  as  described  in  chapter  XXIX,  so  that  if  one  lamp 
should  break  or  be  switched  out,  an  equal  resistance  will 
be  shunted  in  and  an  even  distribution  of  the  current 
among  the  lamps  will  be  kept  up.  In  some  systems  one 
single  distributing  box  is  used  in  place  of  the  single  resist- 
ances and  cut-outs.  The  principle,  however,  is  the  same. 
If  one  or  more  lamps  break  or  are  switched  out,  a  resist- 
ance is  put  between  the  wires  of  the  series  automatically, 
thus  causing  the  same  result,  namely,  keeping  up  a  constant 
strength  of  current  for  each  individual  lamp. 

CHAPTER  XXXII. 
The  Alternating  System. 

In  this  system,  Fig.  26,  alternating  currents  of  high   e. 


I 


itii 


'/V.  (HI 

FIG.  26.  —  ALTERNATING   SYSTEM. 

m.  f.  are  employed.  These  currents  traverse  the  primary 
wires  of  induction  coils  while  the  lamps  are  placed  in  cir- 
cuit with  the  wires  of  the  secondary  coil.  Owing  to  the 
high  e.  m.  f.  employed  in  the  main  conductors  the  latter 
may  be  made  very  small  and  lamps  can  be  run  at  long  dis- 
tance requiring  a  comparatively  small  investment  for  cop- 
per wire. 

The  induction  coils  called  converters  or  transformers  aie 
connected  in  multiple  arc  with  the  mains.  The  incandes- 
cent lamps  are  also  connected  in  multiple  arc  with  the  wires 
starting  from  the  secondary  coil.  Each  lamp  in  this 
system  is  independent  of  the  others  and  may  be  switched 
in  or  out  at  will. 

Arc  lamps  may  be  run  in  this  system  at  the  same  time 
with  incandescent  lamps. 


INSTRUMENTS. 


CHAPTER  XXXIII. 
Current     Indicator    or    Ampere    Meter. 

This  apparatus  is  to  indicate  the  current  strength  at  all 
times.  It  should  be  put  up  in  each  case  where  a  constant 
current  strength  is  requited  as  in  arc  light  circuits  or  m  the 
series  multiple  system  of  incandescent  lighting.  The  in- 
strument must  be  connected  in  series  with  the  arc  lamps  or 
with  the  groups  of  incandescent  lamps  in  the  series  multiple 
system.  It  is  also  used  in  the  multiple  arc  or  multiple 


FIG.  27.  —  POSITION  OF  AMMETER. 

series  system  and  is  always  put  in  one  outgoing  wire  of  the 
dynamo,  Fig.  27. 


CHAPTER    XXXIV. 

Pressure  or  Potential  Indicator,  or  Volt- 
meter. 

This  instrument  is  absolutely  necessary  on  dynamos 
which  must  be  kept  at  a  constant  e.  m.  f.,  as  in  the  multiple 
arc  or  multiple  series  system  of  incandescent  lighting.  The 

39 


40        DYNAMO   TENDERS'  HAND-BOOK. 


instrument  is  connected  in  parallel  with  the  lamps,  as  shown 
m  Fig.  28. 


9     9 


£L£CTfllCMfft  CHf. 


VOLTMETER 


FIG.  28. —  POSITION  OF  VOLTMETER. 


CHAPTER   XXXV. 
Current  Regulator. 

This  instrument,  also  called  rheostat  or  resistance  box, 
consists  of  a  box  which  contains  wire  or  some  other  resist- 
ance and  which  can  be  switched  in  or  out  of  the  electric 
circuit  by  means  of  a  crank.  If  this  is  to  be  done  by  hand, 
the  instrument  is  called  a  hand  regulator  ;  if  done  automat- 
ically it  is  called  an  automatic  regulator. 

The  regulator  for  series  dynamos  is  connected  anywhere 
in  the  circuit,  the  whole  current  generated  by  the  dynamo 
passing  through  it.  By  putting  more  or  less  resistance  in 
the  circuit,  the  current  flowing  through  the  other  parts  of 
the  circuit  can  be  strengthened  or  weakened.  In  shunt 
dynamos  the  regulator  is  put  in  the  shunt  winding  of  the 


FIG.  29. —  SWITCH. 

field.     Putting  in  or  taking  out  the  resistance' decreases  or 
increases  the  strength  of  the  field  magnets  and  thus  con- 


INSTRUMENTS.  41 

trols  the  current  generated  in  the  armature.  In  some  arc 
light  dynamos  the  regulation  of  the  current  is  effected  by 
putting  more  or  less  resistance  in  shunt  with  the  field  cir- 
cuit, and  in  others  by  automatic  devices  for  shifting  the 
brushes.  The  movement  of  the  latter  towards  the  neutral 
point  will  increase  the  current,  while  moving  them  in  an 
opposite  direction  will  decrease  the  current  strength.  [See 
Chapter  XVIII,  Fig.  13.] 

CHAPTER  XXXVI. 
Switches. 

A  switch  is  an  instrument  to  break  or  make  circuit,  or, 
in  other  words,  to  cut  off  the  current  in  certain  places  for  a 
number  of  lamps  or  cut  them  in  again.  The  switches 
should  be  constructed  so  that  they  will  open  and  close  very 
quickly  and  not  show  very  much  sparking.  [See  Fig.  29.] 
This  is  accomplished  by  having  the  switch  so  arranged 


FIG.  30.  —  TWO-WAY  SWITCH. 

that  the  human  hand  will  start  it,  while  a  powerful  spring 
throws   the   switch  open   or   closes  it  immediately. 


The 


42        DYNAMO    TENDERS'  HAND-BOOK. 

contact  should  be  sufficient  to  prevent  any  heating  at  these 
points. 

Two-way  switches  are  used  in  various  ways ;  for  in- 
stance, for  two  different  sets  of  lamps.  It  one  set  of 
lamps  is  not  required,  the  handle,  as  shown  in  Fig.  30,  is 
moved  from  A  to  B>  and  the  lamps  marked  X  will  go  out, 
while  those  marked  Y  will  be  started. 

CHAPTER    XXXVII. 
Safety  Devices. 

Strips  of  an  alloy  which  fuses  at  a  low  temperature  are 
used  as  safety  devices,  or  plugs,  in  incandescent  wiring. 
The  cross-section  of  the  plug'  must  be  of  such  size 


FIG.  31.  —  POSITION  OF  SAFETY  PLUGS. 

that  it  will  melt  before  the  wire  it  protects  gets 
dangerously  warm.  Hence,  the  diameter  of  the  safety 
plug  depends  upon  the  cross-section  of  the  wire  to  be  pi  o- 
tected  and  not  upon  the  number  of  the  lamps.  The  safety 
plug  is  not  supposed  to  protect  incandescent  lamps  from 
an  excess  of  current,  but  to  protect  the  building  from  fire 
by  preventing  any  part  of  the  electric  light  conductors 
from  getting  too  hot.  The  marking  of  safety  plugs  with 
the  number  of  lamps  they  can  carry  has  misled  many  an 
employe  of  an  electric  light  company  to  think  that  the 
plugs  are  put  in  for  the  protection  of  a  certain  number  of 
lamps.  The  marking  of  the  plugs  simply  expresses  their 
carrying  capacity  in  16  candle  power  lamps  instead  of  in 
amperes.  See  Fig  31,  in  which  safety  plugs  are  marked  S. 


INSTRUMENTS. 


The  blowing  out  of  safety  plugs  is  very  often  caused,  not 
by  an  excess  of  current,  but  by  poor  contact  between  safety 
plug  and  safety  plug  holder.  A  poor  contact,  of  course, 
will  generate  heat,  which  will  gradually  fuse  the  metal  on 
one  end.  It  is  best  to  have  double  pole  safety  plugs. 

CHAPTER  XXXVIII. 
Lightning  Arresters. 

Where  electric  light  lines  are  put  up  outside  of  buildings 
they  are  liable  to  be  struck  by  lightning.  To  meet  such  a 
contingency,  the  dynamo  and  station 
apparatus  are  protected  by  a  lightning 
arrester.  Fig.  32  shows  the  simplest 
form  of  a  lightning  arrester  ;  D  repre- 
sents the  dynamo  ;  A  and  B  are  brass 
plates,  through  which  the  two  outgo- 
ing wires  pass,  and  C  is  a  brass  plate 
connecting  to  moist  earth.  The  space 
between  the  toothed  sides  of  A  and  B 
and  the  center  plate  C  is  adjusted  to 
the  thickness  of  a  piece  of  card  board. 
If  lightning  should  come  in  on  one  of 
the  wires,  it  would  leap  over  this  nar- 
row space  and  run  into  the  ground 
without  doing  any  serious  mischief. 
Such  an  arrester  will  keep  the  lines 
discharged,  and  very  often  during  a 
thunder  storm  the  atmospheric  elec- 
tricity will  continuously  leap  across 
these* plates  in  the  form  of  blue,  sparks. 
These  discharges  may  sometimes 
cause  the  center  plate  to  fuse  to  one  or 
even  both  toothed  plates.  In  the  lat- 
ter case,  the  current  of  the  dynamo 
may  follow  the  arcs  which  are  simulta- 
neously set  up  between^,  C  and  B, 
C.  If  the  center  plate  should  be  fused 
to  both  toothed  plates  the  dynamo 
would  be  short-circuited  through  A, 
C,  B,  and  the  belt  would  be  thrown 
off  or  the  armature,  and  possibly  some 
of  the  instruments  in  the  circuit,  might 
FIG.  32.— LIGHT-  be  burned. 

KING  ARRESTER. 


44        DYNAMO   TENDERS'  HAND-BOOK. 

In  order  to  prevent  such  an  accident,  numerous  devices 
have  been  designed  to  operate  in  connection  with  the 
lightning  arrester.  They  may  be  classified  as  follows  : 

First,  Safety  fuses  inserted  between  the  dynamo  and  the 
strips  A  and  B.  They  will  fuse  when  the  dynamo  is  short- 
cuited,  break  the  current  and  thus  save  the  armature. 

Secondly,  Electro-magnets  which  are  energized  when  the 
dynamo  is  short-circuited  and  open  the  circuit. 

Thirdly,  Devices  which  will  extinguish  any  electric  arc 
that  might  be  formed  between  C  and  A  or  C  and  B.  Such 
devices  are  based  on  the  principle  that  a  magnet  will 
attract  the  electric  arc  and  pull  it  away  from  the  plates  A 
and  C  or  B  and  C. 

Whatever  devices  are  used,  one  important  point  should 
not  be  overlooked.  This  is  the  absolute  necessity  of  a 
good  earth  contact.  The  wire  leading  from  C  to  earth 
should  be  at  least  a  number  4  Brown  &  Sharpe  copper  wire. 
This  wire  should  be  solidly  connected  and  soldered  to  a 
galvanized  iron  plate  al  least  %  incn  thick  and  having  an 
area  of  at  least  ten  square  feet  on  each  side.  If  a  pipe  is 
used  instead  of  a  plate,  the  internal  area  is  not  to  be  con- 
sidered, but  twenty  square  feet  of  external  area  is  neces- 
sary. This  earth  plate  should  be  sunk  so  deeply  in  the 
earth  that  even  during  a  dry  season  it  will  always  be  in 
moist  ground.  A  well  or  a  stream  of  water  is  preferable. 
The  earth  wire  should  also  be  connected  to  water  pipes  or 
gas  pipes  if  they  are  near  by.  Such  a  connection,  how- 
ever, is  not  a  substitute  for  the  earth  plate,  which  is  a 
necessity  under  any  circumstances. 

The  conductor  of  the  lightning  rod  of  a  building  must 
not  be  connected  with  the  earth  wire  of  a  lightning 
arrester. 

All  connections  underground  must  be  soldered  and  then 
painted  with  asphaltum  to  prevent  corrosion  and  poor 
contacts.  Poor  connections  with  the  earth  are  very  often 
the  cause  of  the  unsatisfactory  working  of  lightning  arresters. 

It  should  be  borne  in  mind  that  no  lightning  arrester  is 
an  absolute  safeguard  against  the  freaks  of  lightning. 
Very  long  circuits,  especially  those  not  protected  by  tall 
buildings  or  trees,  are  very  liable  to  be  struck  by  lightning. 
In  such  cases  extra  devices  at  some  points  along  the  line 
must  be  put  up  as  an  additional  protection. 

The  jaws  of  the  lightning  arrester  should  be  kept  clean 
and  at  a  proper  distance.  It  is  advisable  to  run  a  card- 
board between  the  plates  every  day  to  make  sure  that  the 
jaws  are  at  a  proper  distance  from  each  other. 


INSTRUMENTS.  45 

CHAPTER  XXXIX. 
Ground  Detector. 

It  is  absolutely  necessary  to  test  electric  light  circuits 
frequently,  and  this  means  at  least  once  a  day,  for  grounds. 
In  incandescent  light  installations  which  run  continuously, 
arrangements  to  indicate  a  ground  while  the  dynamo  is 
running  should  be  made.  A  simple  form  of  ground  detector 
is  shown  in  Fig.  33.  Two  lamps  are  connected  in  series 


FIG.   33.  —  GROUND  DETECTOR. 

between  the  mains  near  the  dynamo.  A  wire  leading  to 
earth  is  connected  between  the  two  lamps  ;  a  safety  plug 
and  a  switch  are  put  into  the  earth  wire.  If  there  is  no 
ground  on  the  line  the  two  lamps  will  burn  very  dimly  but 
at  equal  candle  power.  If  a  ground  should  occur  anywhere 
in  the  circuit,  say  on  the  positive  pole,  the  earth  wire 
and  the  ground  will  form  a  shunt  of  low  resistance  to  the 
lamp  nearest  the  positive  wire  ;  the  result  will  be  that  lamp 
A  will  dim  down  and  lamp  B  will  brighten  up.  Sometimes 
it  may  occur  that  both  poles  of  a  circuit  are  grounded  and 


46        DYNAMO    TENDERS'  HAND-BOOK. 


that  the  grounds  are  of  about  equal  resistance.  In  such  a 
case  the  two  lamps  will  burn  equal  y  dimly.  By  switching 
out  one  lamp,  however,  it  can  be  seen  whether  the  lines  are 
grounded  or  not  If  the  other  lamp  also  goes  out  the 
lines  are  not  grounded,  but  if  the  other  lamp  continues  to 
burn  the  lines  are  grounded  on  both  poles.  To  make  this 
test  one  lamp  should  be  provided  with  a  socket  with  key. 
Instead  of  two  lamps  a  galvanometer  with  two  coils  con- 
nected in  the  same  manner  as  the  two  lamps  may  be  used. 
The  needle  will  stand  at  zero  when  there  is  no  ground  on 
the  line  and  deflect  as  soon  as  the  wire  gets  grounded.  Any 
grade  of  sensitiveness  may  be  given  such  an  instrument. 

CHAPTER  XL. 
Switch-Board. 

A  switch-board  is  used  in  larger  plants  to  connect  any 
dynamo  with  any  circuit.  Of  course  only  dynamos  of  the 
same  kind  can  be  made  interchangeable.  For  arc  lamp 
plants,  plug  switch-boards  are  generally  employed.  Short 
cables  with  a  plug  on  each  end  caa  he  inserted  in  the  differ- 


D2 


» 
c2! 


W&TCffM  eiECr/1/CMN.  CHt. 

FIG.  34.  —  SWITCH  -  BOARD. 

ent  sockets.     The  latter  are  marked  with  +  or  — ,  and  with 
D  (dynamo),  C  (circuit).  In  addition,  they  are  marked  with  a 


INSTRUMENTS.  47 

number.  For  instance,  D  I  (meaning  dynamo  number  i) 
can  be  connected  to  C  2  (circuit  number  2),  and  so  on. 
Fig.  34  is  a  diagram  showing  the  arrangement  of  a  switch- 
board. 

In  incandescent  plants  large  lever  switches  are  generally 
used,  as  large  enough  plugs  could  not  be  conveniently 
made  to  carry  the  heavy  currents  of  incandescent  circuits. 


CIRCUITS   OR    LEADS. 


CHAPTER   XLI. 
Outdoor  Leads  for  Arc  Lighting, 

The  wire  used  for  outdoor  circuits  is  mostly  what  is  called 
anderwriters'  standard.  It  consists  of  a  copper  wire  which 
is  braided  with  cotton  and  painted  with  asbestos  to  make  it 
uninflammable.  This  wire  is  fastened  to  glass  insulators 
on  poles  or  houses  in  a  way  similar  to  that  in  which  tele- 
graph wires  are  usually  run.  Insulated  wire,  and  not  bare 
wire,  should  be  used  for  tie  wire,  as  the  common  non- 
insulated  tie  wire  will  cut  the  insulation  of  the  line  wire 
and  possibly  cause  leaks.  The  size  of  arc  light  conductors 
varies  between  numbers  6  and  4,  Brown  &  Sharpe  gauge, 
number  6  being  the  smallest  wire  which  can  be  used, 
according  to  the  rules  of  the  National  Board  of  Fire  Under- 
writers. If  the  return  wire  is  fastened  on  the  same  poles, 
the  positive  and  negative  wires  should  be  kept  sufficiently 
far  apart  so  they  can  not  touch  each  other  when  swung  by 
wind.  It  must  be  understood  that  the  insulation  called 
underwriters'  standard  is  only  an  insulation,  when  per- 
fectly dry, and  when  wet  is  hardly  any  insulation  at  all.  If, 
therefore,  the  positive  and  negative  wires  exposed  to  rain 
or  moisture  of  any  kind  should  come  in  contact  with  each 
other  or  with  the  ground,  a  short  circuit  would  be  caused. 
This  may  cut  a  number  of  lamps  suddenly  out  and  cause 
damage  to  the  dynamo.  Such  an  accident,  for  instance, 
may  burn  out  the  armature  or  throw  off  the  belt.  In  very 
cold  weather  such  occurrences  are  rare,  as  frost  may  make 
out  of  a  circuit  of  the  poorest  insulation  one  of  very  high 
insulation,  while  on  the  other  hand  a  thaw  or  rain  may 
cause  all  kinds  of  disturbances.  If  these  disturbances  occur 
during  a  thunder  storm  accompanied  by  rain,  lightning  is 
often  unjustly  accused  of  having  done  the  mischief,  while 
in  fact  the  poor  insulation  of  the  wires  is  the  prime 
cause. 

Accidents  from  poor  insulation  of  lines  are  more  frequent 
than  damages  caused  by  lightning,  though  the  latter  will 
48 


CIRCUITS  OR  LEADS. 


49 


always  be  a  ready  excuse  for  anything  that  may  have  hap- 
pened. Recently  weather  and  water-proof  insulation  have 
come  in  vogue,  and  they 
are  much  safer  than  under- 
writers' standard  wire. 

In  conducting  wires  into 
houses,  great  care  must  be 
taken  to  prevent  rain  follow- 
ing the  wires.  The  wire 
should  be  fastened  to  the 
insulator  below  the  point 
where  it  is  intended  to  be 
led  through  the  wall  or  a 
window  frame,  so  the  rain 
would  have  to  run  up  hill  in 
order  to  follow  the  wire, 
Fig.  35. 

FIG.  35,  —  PROPER  POSI- 
TION OF  INSULATOR. 


Fig.  36  shows  a  wood 
pin  and  glass  insulator, 
such  as  are  used  on  cross- 
arms.  The  latter  are  fast- 
ened to  poles  by  means  of 
|lag  screws.  Fig.  37  illus- 
'trates  a  wood  bracket, 
which  can  be  spiked  to 
poles  or  houses  ami  pro- 
vided with  a  glass  insulator. 
The  glass  insulators  must 
always  be  fastened  in  a 
nearly  vertical  position,  the 
closed  end  on  top,  so  the 
space  between  the  pin  and 
glass  insulator,  Fig.  36, 
will  remain  dry  in  rainy 
weather  and  secure  perfect 
insulation. 


FIG.  36. —WOOD  | 
PIN  AND  GLASS  I, 
INSULATOR. 


FIG.  37. — WOOD  BRACKET. 


50        DYNAMO    TENDERS'  H AMD-BOOK. 

Fig.  38  shows  a  rubber  hook  insulator.     This  should  for 
the  same  reason  be  fastened  with  the  hook  downward      A 


FIG.  38.  —  RUBBER  HOOK  INSULATOR. 

hole  can  be  bored  with  a  $  inch   bit  underneath  a  cross- 
arm  and  the  rubber  hook  screwed  in  with  a  wrench. 

An  extra  heavy  insulating  material,  such  as  rubber  hose 
or  hard  rubber  or  porcelain  tube,  Fig.  39,  must  be  put  over 
the  wires  where  they  pass  through  walls  or  partitions. 


FIG.  39.  —  HARD  RUBBER  TUBE. 

Poles  for  lines  should  be  set  deep  enough  in  the  ground; 
the  depth,  of  course,  will  depend  upon  the  soil  and  the 
height  of  the  pole.  In  sand,  at  least  one-fifth  of  the  length 
of  the  pole  should  be  buried  in  the  ground,  while  in  rock 
one-tenth  of  the  length  is  sufficient.  In  putting  up  wires, 


CIRCUITS  OR  LEADS. 


the  season,  or,  in  other  words,  the  temperature,  should  be 
taken  into  consideration,  allowing  for  contraction  in  cold 
weather.  If,  for  instance,  a  wire  should  be  put  up  very 
tight  in  July,  it  would  cause  a  good  deal  of  damage  in 
breaking  off  glass  insulators  and  pins  as  soon  as  the  tem- 
perature fell  to  zero  and  caused  the  wire  to  contract.  Cor- 
ner poles  must  be  braced  or  anchored  to  keep  them  in  a 
nearly  vertical  position.  See  Figs.  40  and  41. 


FIG.  40.  —  CORNER  POLE  ANCHORED. 

When  a  splice  is  necessary,  it  should  be  made  after  the 
fashion  of  the  American  telegraph  splice,  Fig.  42,  and 
should  be  perfectly  clean  and  solidly  soldered  and  then 
well  taped  with  insulating  tape.  In  order  to  prevent  the 
tape  from  peeling  off,  it  is  advisable  to  fasten  the  last  turns 


$2        DYNAMO    TENDERS'  HAND  BOOK. 

of  the  tape   to  the  wire  writh  a  few  turns  of  bare  coppei 
wire,  say  about   number  20.     If  this  precaution  is  omittec 


FIG.  41  —CORNER  POLE  BRACED. 

the  tape  is  sure  to  peel  off  in    time.     Most   of  our  electric 
light   lines  will    show  places  where   the   taps    is   hanging 


FIG.  42. —  AMERICAN  TELEGRAPH  SPLICE. 

down  a  couple  of  feet.  Besides,  having  no  insulation  on 
the  splice,  this,  of  course,  does  not  contribute  to  the  beauty 
of  overhead  wires. 

Brass   line   connectors,    Fig.  43,  are   only   allowed   for 


CIRCUITS  OR  LEADS.  53 

inside  work  where  there  is  no  strain  on  the  wires,  The 
set  screws  should  be  well  tightened,  and  the  connector  be 
run  full  of  solder  and  taped.  Good  soldering  and  taping 


FIG.  43.  — BRASS  LINE  CONNECTOR. 

of  joints  will  save  at  least  50  per  cent,  of  all  the  troubles 
that  occur  in  an  electric  light  plant.  Joints  should  never 
be  left  unsoldered,  even  if  persons  who  claim  to  know  all 
about  it  should  think  it  unnecessary.  The  best  apparatus 
for  soldering  joints  on  line  wire  out  of  doors  is  the  gasoline 
blow-pipe,  Fig.  44.  Every  trace  of  acid  should  be  wiped 


FIG.  44.  —  GASOLINE  BLOW-PIPE. 

off  the  wire  with  a  moist  or  oily  cloth  before  taping,  to 
avoid  corrosion. 

CHAPTER   XLII. 

Outdoor  Leads  for  Incandescent  Light- 
ing. 

*  The  rules  which  were  given  for  outdoor  arc  light  lines 
can  be  applied  for  incandescent  light  lines.  As  the  wire 
used  will  very  often  be  considerably  larger  than  number  4 


54         DYNAMO    TENDERS'   HAND-BOOK. 

wire,  the  poles,  cross-arms  and  other  supports  must  neces- 
sarily be  heavier  to  stand  the  greater  strain,  and  poles 
should  be  set  closer  together.  In  a  low  tension  incandes- 
cent system,  very  often  bare  wires  are  used,  and  still  more 
care  must  be  taken  to  prevent  accidental  contact  of  the 
positive  and  negative  wires  with  each  other  or  with  the 
earth. 


CHAPTER  XLIII. 
Arc  Circuits  Inside  of  Houses. 

The  wires  for  these  circuits  should  be  fastened  to  porce- 
lain insulators,  Fig.  45,  and  be  exposed  to  view.     Owing 


FIG.  45.  —  PORCELAIN    INSULATOR. 

to  the  high  tension  which  prevails  in  arc  light  circuits,  the 
concealing  of  these  wires  is  not  permitted  by  the  under- 
writers. The  directions  given  for  splicing  and  insulating 
hold  good  also  for  inside  wiring. 

In  rooms  which  are  exposed  to  steam  or  moisture,  as,  for 
instance,  in  packing  houses,  wire  with  a  better  insulation 
than  underwriters'  standard  must  be  used.  The  moisture 
which  covers  insulators  and  wire  would  cause  considera- 
ble leakage,  and,  besides,  would  corrode  the  wire.  The 
use  of  wood  cleats  or  iron  staples  instead  of  porcelain 
insulators  should  not  be  permitted  in  any  case,  as  they  are 
liable  to  cause  grounds  and,  in  fact,  have  been  the  source 
of  mischief  in  a  good  many  cases  in  years  gone  by. 


CIRCUITS  OR  LEADS.  55 

CHAPTER   XLIV. 
Incandescent  Circuits  Inside  of  Houses. 

In  the  low  tension  systems,  wooden  cleats  or  wooden 
molding  are  permitted  for  fastening  the  wires  to  the 
walls  and  ceilings  if  there  is  absolute  safety  from  moisture. 
Underwriters'  wire  may  be  used  also  under  the  same  con- 
ditions. If  there  is  any  possibility  of  moisture  getting  to 
the  wires,  the  latter  should  be  first-class  waterproof  insula- 
tion. If  any  "  fishing  "  has  to  be  done,  where  wires  are  to  be 
concealed  under  floors,  above  ceilings,  or  between  walls  or 
laths,  only  waterproof  wire  can  be  used.  Incandescent  wir- 
ing inside  of  houses  requires  a  good  deal  of  skill  and  experi- 
ence, and  should  only  be  intrusted  to  reliable  and  responsible 
concerns.  Unfortunately,  any  man  who  ever  fastened  a 
piece  of  wire  for  a  bell-pull,  thinks  himself  an  expert  also 
for  incandescent  wiring  ;  a  good  many  even  important  jobs 
have  been  done  by  such  men,  with  the  result  that,  after  a 
great  expenditure  of  money  by  the  owner  of  the  house,  the 
whole  system  had  to  be  condemned,  as  not  an  inch  of  the 
wire  had  been  put  in  properly  and  could  be  used. 

The  joints  or  connections  in  waterproof  wire  should  be 
made  waterproof  also.  This  is  done  in  the  following  way  : 
After  having  spliced,  soldered  and  cleaned  the  wires  prop- 
erly, cover  the  joint  with  hot  Chatterton's  compound  by 
molding  it  between  the  fingers  to  almost  the  total  thickness 
of  the  insulated  wire.  Then  cover  it  with  kerite  tape  and 
give  it  a  second  thin  coating  with  hot  compound,  or  hot 
asphaltum,  and  then  give  it  a  second  coat  of  kerite  tape. 
Hot  liquid  asphaltum  should  be  used  in  lieu  of  compound 
where  there  is  danger  from  sewer  or  illuminating  g#s  that 
is  prevalent  in  the  soil  and  basements  of  houses  in  large 
cities. 


FIG.  46. — WOOD  CLEAT. 

Figs.  46,  47,  48,  49  and  50  show  the  use  of  cleats.     Fig. 
46  shows  a  familiar  form  of    cleat.     Where   the   positive 


56        DYNAMO    TENDERS'  HAND-BOOK. 

wire  crosses  the  negative,  an  extra  protection  of  rubber 
tube  is  required  to  prevent  any  danger  from  short  circuits, 
Fig.  47 


FIG.  47.  —  PROTECTION  OF  WIRES  CROSSING  EACH 

OTHER. 

In  passing  through  a  wall,  each  wire  should  be  inserted 
in  a  separate  hole,  lined  with  a  hard   rubber  tube,  Fig.  48, 


II. 


II 


.  <z> 


u      Tr 

FIG.  48.  — WIRES  IN  FIG.  49.  — WIRES  IN 

SEPARATE    HOLES.  SAME   HOLE. 

or  each  wire  should  be  covered  with  soft  rubber  tubing  and 
both  may  be  drawn  through  one  hole,  Fig.  49,  lined  with  a 
pipe  of  non-conducting  waterproof  material. 


FIG.  50. — WOOD  MOLDING. 

Fig.  50  is  a  cross-section  of  wood  molding.     The  lower 
part  is  fastened  to  the  \vall  or  ceiling,  the   wires  put  in — 


r* / f> s* j -7 •-- en c~    -^  z?     -  •?  s  ,r>  f  .  ».j 

positives  in  one  groove  and  negatives  in  the  other — and 
the  cover  screwed  on.  Care  must  be  taken  that  nails  or 
screws  do  not  touch  the  wires. 

The  safety  plugs  are  put  in  the  circuit  according  to  the 
rules  of  the  fire  underwriters.  They  must  be  of  such  size 
that  they  will  fuse  before  the  wire  they  have  to  protect  can 
get  dangerously  warm. 

CHAPTER  XLV. 

Size  of  Wires  for   Incandescent   Lamp 
Installations. 

The  wire  for  each  main  or  branch  must  be  of  such  size 
that  it  can  carry  the  current  to  the  lamps  which  are  con- 
nected to  it,  without  getting  very  warm.  The  number  of 
amperes  a  wire  can  thus  safely  carry  is  called  its  carrying 
capacity. 

In  the  table  on  page  70,  the  carrying  capacity  is  given 
in  Column  XIV.  A  number  4  B.  &  S.  copper  wire,  for  in- 
stance, can  carry  50  amperes  ;  its  temperature  will  then  in- 
crease 1 8  degrees  Fahrenheit.  But  besides  the  carrying 
capacity  something  else  must  be  taken  into  consideration. 
This  is  the  amount  of  energy  which  will  be  allowed  as  loss 
in  the  wires.  The  larger  the  wire  the  less  the  loss  ;  the 
smaller  the  wire  the  higher  the  loss.  In  house  wiring  not 
more  than  5  per  cent,  loss  should  be  allowed  from  the  dy- 
namo to  the  lamp. 

For  those  who  want  to  give  this  matter  more  study  the 
following  formulas  are  given.  Any*one  who  understands 
arithmetic  will  be  able  to  calculate  the  size  of  wire  for  any 
loss  and  for  any  lamp  :  • 

n  =  number  of  lamps. 

d  =  distance  —  Yz  length  of  circuit. 

%  —  energy  lost  in  the  conductors,  expressed  in  decimal 
fractions  of  100  as  5$  =  .05. 

r  —  resistance  in  ohms. 

r  of  lamp  hot  X  % 

1 .  r  of  wire  — 

•x  n 

2.  Length  of  wire  :  1000  =  r  of  wire  :  r  per  1000  feet. 

r  of  lamp  hot  X  %  X  1000, 

3.  r  per  1000  feet  of  wire  =  £- '-— • 


4.     r  per  1000  feet  of  wire  = 


n  X  2  X  d 

constant, 


X  d 
5.     Constant  =  500  X  %  X  r  of  lamp  hot. 


58         'DYNAMO    TENDERS'    HAND-BOOK. 

EXAMPLE  :  Find  size  of  wire  necessary  to  carry  40  six- 
teen candle  power  lamps  (r  =  167  ohms  hot),  500  feet, 
Lofc  loss. 

Formula  5  :  Constant  =  500  X  .io.X  167  =  8350. 

Formula  4:  r  per  1000  feet  ~  - —  =  .417  ohms. 

40  X  500. 

This  is  the  resistance  per  1000  feet  of  the  wire  necessary 
to  use.  Find  the  next  smaller  number  in  Column  XI  of 
table  on  page  70 — this  is  .411. 

The  number  of  wire  on  same  line  in  Column  I  of  the 
table  is  the  proper  size. 

In  this  case  No.  6  wire. 

If  the  resistance  hot  of  the  lamp  should  not  be  known  it 

E  E 

can  be  calculated  from  Ohm's  law.     C  =  —  or  R  =    —  • 

lx  V^ 

Supposing  the  e.  m.  f.  —  100  volts  and   the  current  —  — 

,  100  x  10 
amperes,  R  would  equal  —    ,  or  Ra=  200. 


CHAPTER   XLVI. 
Testing. 

The  circuit  should  be  tested  every  day  for  grounds  by 
means  of  the  detector  galvanometer  or  a  magneto  bell.  If 
a  ground  is  indicated  it  should  be  speedily  located  by  dis- 
connecting the  circuit  in  different  places  and  taking  each 
section  separately,  until  the  ground  is  located.  [See  also 
Chapter  XXXIX.] 


A  CCUM  VLA  TOA'S.  59 

CHAPTER   XLVII. 
Accumulators. 

Accumulators,  Fig.  51,  or  secondary  batteries,  are  used 
for  the  storage  of  electricity.  They  consist  generally  of 
glass  vessels  containing  a  solution  of  sulphuric  acid  and 
water  in  which  lead  plates,  insulated  from  each  other,  are 
placed  The  positive  and  negative  lead  plates  are  called 
the  electrodes.  These  batteries  are  usually  charged  with 
shunt  dynamos.  A  chemical  change  in  the  plates  is  pro- 
duced. In  discharging,  the  plates  try  to  return  to  their 
first  chemical  condition  and  in  doing  so  they  generate  a 
current. 


FIG.  51.  —  ACCUMULATORS. 


The  e.  m.  f.  of  an  accumulator  is  about  2  volts.  In  or- 
der to  burn  100  volt  lamps,  50  accumulators  must  be  con- 
nected in  series.  The  maximum  current  strength  they 
should  be  allowed  to  yield  is  generally  given  by  the  manu- 
facturer. It  is  in  the  neighborhood  of  35  amperes,  which 
can  be  yielded  for  ten  hours,  or,  as  it  is  expressed  the  accu- 
mulators can  yield  35  x  10  =  350  ampere  hours.  Hence 
a  battery  of  50  accumulators  could  yield  350  ampere 
hours  at  100  volts  pressure.  If  we  had  100  volt  16  candle 
power  lamps  requiring  yz  ampere  each,  we  could,  for  in- 
stance, burn  70  of  these  lamps  10  hours,  or  35  lamps  20 
hours,  etc. 


SAFETY  REGULATIONS. 


Rules  of  the  Boston  Underwriters'  Union.1 

ARC  LIGHT  WIRES. 

Conducting  wires  must  be  seven  feet  above  roofs,  and 
placed  so  as  to  avoid  ladders  of  the  fire  department  and  fire 
shutters. 

Whenever  electric  light  wires  are  in  proximity  to  other 
wires,  dead  guard  wires  must  be  placed  so  as  to  prevent 
any  possibility  of  contact  with  foreign  wires,  in  case  of  ac- 
cident to  the  wires  or  their  supports.  Conducting  wires 
must  be  secured  to  insulating  fastenings,  and  covered  with 
an  insulation  which  is  waterproof  on  the  outside  and  not 
easily  worn  by  abrasion.  Whenever  wires  pass  through 
walls,  roofs,  floors  or  partitions,  or  there  is  liability  to 
moisture,  abrasion,  or  exposure  to  rats  and  mice,  the  insul- 
ation must  be  protected  with  rubber,  stoneware  or  some 
other  satisfactory  material.  Wires  entering  buildings  must 
be  wrapped  with  tape  and  bent  in  such  a  manner  that  it 
will  prevent  the  water  entering  the  building.  All  wires 
passing  over  or  under  steam,  gas  or  water  pipes,  must  have 
a  good  insulation  between  them  and  the  pipes.  Blocks  of 
wood  are  the  most  desirable.  This  rule  also  applies  to 
foreign  wires — they  should  be  treated  the  same  as  pipes. 

Wires  should  go  over  water  pipes,  where  it  is  possible, 
so  that  the  moisture  will  not  settle  on  the  wires. 

Hard  rubber  hooks  are  not  desirable  as  fastenings,  and 
tacks  or  staples  must  in  no  case  be  used  for  fastenings  or 
brought  in  contact  with  the  wire. 

In  damp  places,  wires  must  be  run  on  glass  insulators, 
and  kept  entirely  clear  from  contact  with  inflammable  ma- 
terial and  any  substance  likely  to  make  a  ground  connec- 
ti:>n. 

The  use  of  lead  covered  wires,  or  wires  whose  covering 
contains  paraffine,  is  prohibited. 

The  use  of  underwriters'  wire  will  not  be  passed  where  it 
is  concealed  in  any  manner.  It  must  be  in  plain  sight,  on 
the  walls  or  ceilings.  Wire  that  is  covered  with  molding 
must  have  a  water-proof  insulation  that  is  approved  by  this 
union. 

lApproved,  November  1. 1887. 

60 


SAFETY  REG U LA  TIONS.  61 

Joints  in  wires  to  be  securely  made  and  wrapped  with 
tape  ;  soldered  joints  are  desirable  but  not  essential.  Wires 
conducting  electricity  for  arc  lights  must  not  approach  each 
other  nearer  than  one  foot. 

Care  must  be  taken  that  the  wires  are  not  placed  above 
each  other  in  such  a  manner  that  water  could  make  a  cross 
connection. 

Cut-off  boxes  for  arc  lights  must  have  the  words  "  On  " 
and  "Off  "  marked  on  them.  They  must  be  placed  in  a  well- 
protected  and  accessible  place,  so  that  they  can  be  operated 
by  the  firemen  or  police. 

ARC   LAMPS. 

For  arc  lamps,  the  frames  and  other  exposed  parts  of  the 
lamps  must  be  insulated  from  the  circuit.  Each  lamp  must 
be  provided  with  a  separate  hand-switch,  and  also  with  an 
automatic  switch,  which  will  close  the  circuit  and  put  the 
lamp  out  whenever  the  carbons  do  not  approach  each  other, 
or  the  resistance  of  the  lamp  becomes  excessive  from  any 
cause.  The  lamps  must  be  provided  with  some  arrange- 
ment or  device  to  p  event  the  lower  carbons  from  falling 
out,  in  case  the  clamp  should  not  hold  them  securely. 

For  inside  use,  the  light  must  be  surrounded  by  a  globe, 
which  must  rest  in  a  tight  stand,  so  that  no  particles  of 
melted  copper  or  heated  carbon  can  escape;  and  when  near 
combustible  material,  this  globe  must  be  protected  by  a 
wire  netting.  Broken  or  cracked  globes  must  be  replaced 
immediately.  Unless  a  very  high  globe  is  used,  which 
closes  in  as  far  as  possible  at'the  top,  it  must  be  covered 
by  some  protector,  reaching  to  a  safe  distance  above  the 
light 

INCANDESCENT   WIRES. 

Conducting  wires  must  be  seven  feet  above  roofs,  and 
placed  so  as  to  avoid  ladders  of  the  fire  department  and  fire 
shutters.  All  connections  must  be  soldered  and  wrapped 
with  tape. 

Whenever  the  electric  light  wires  are  in  proximity  to 
other  wires,  dead  guard  wires  must  be  placed  so  as  to  pre- 
vent any  possibility  of  contact  with  foreign  wires,  in  case 
of  accident  to  the  wires  or  their  supports.  Conducting 
wires  must  be  secured  to  insulating  fastenings,  and  covered 
with  an  insulation  which  is  water-proof  on  the  outside  and 
not  easily  worn  by  abrasion.  Whenever  wires  pass  through 
walls,  roofs,  floors  or  partitions,  or  there  is  liability  to 
moisture,  abrasion,  or  exposure  to  rats  and  mice,  the  insu- 
lation must  be  protected  with  rubber,  stoneware  or  some 


62         DYNAMO    TENDERS'  HAND-BOOK. 

other  satisfactory  material.  Wires  entering  buildings  must 
be  wrapped  with  tape,  and  bent  in  such  a  manner  that  it 
will  prevent  the  water  entering  the  building.  All  wires 
passing  over  or  under  steam,  gas  or  water  pipes,  must  have 
a  good  insulation  between  them.  Blocks  of  wood  are  the 
most  desirable.  This  rule  also  applies  to  foreign  wires — 
they  should  be  treated  the  same  as  pipes. 

Soft  rubber  tube  is  not  desirable  as  an  insulator. 

Wires  should  go  over  water  pipes,  where  it  is  possible,  so 
that  the  moisture  will  not  settle  on  the  wires. 

'Where  incandescent  wires  enter  buildings,  they  must 
have  double-poled  safety  catches  as  near  the  entrance  as 
possible. 

The  main  wires  must  not  be  less  than  two  and  a  half 
inches  apart,  except  where  they  are  in  grooves. 

The  use  of  lead  covered  or  wires  whose  covering  contains 
paraffine  is  prohibited. 

All  wires  that  are  fished  over  the  ceiling  or  in  the  wails, 
must  have  a  water-proof  insulation  satisfactory  to  this 
union.  This  rule  als  >  applies  to  wires  covered  with  mold- 
ing, or  concealed  in  any  manner. 

Where  underwriters'  wire  is  used,  it  must  be  in  plain 
sight  on  the  walls  or  ceilings 

Care  must  be  taken  that  the  wires  are  not  placed  above 
each  other  in  such  a  manner  that  water  could  make  a  cross 
connection. 

Wires  that  are  run  in  damp  places  must  be  run  on  glass 
or  porcelain  insulators  of  suitable  form. 

For  incandescent  lamps,  the  conducting  wires  leading  to 
each  building,  and  to  each  important  branch  circuit,  must 
be  provided  with  an  automatic  switch  or  cut-off,  or  its 
equivalent,  capable  of  protecting  the  system  from  any  in- 
jury due  to  an  excessive  current  of  electricity.  These  de- 
vices must  be  proportioned  to  protect  the  smallest  wire  in 
the  loop  to  which  they  are  attached. 

On  all  loops  of  incandescent  circuits,  safety  catches  must 
be  used  on  both  sides  of  the  loop,  and  switches  on  such 
loops  should  be  double-poled. 

Ceiling  blocks  that  are  used  on  pendant  drops  must  have 
safety  metals  in  them  where  flexible  cord  is  used.  Cord 
should  have  a  knot  tied  in  it  with  the  knot  on  the  top  side 
of  the  block,  so  that  the  strain  will  come  on  the  knot  instead 
of  on  the  connection  ;  and  where  it  is  possible,  a  knot  should 
be  inside  of  the  socket,  the  same  as  the  block. 

The  small  wires  leading  to  each  lamp  from  the  main  wires 


SAFETY  REGULATIONS.  63 

must  be  thoroughly  insulated,  and  if  separated  or  broken, 
no  attempt  made  to  join  them  while  the  current  is  in  the 
main  wires. 

When  wires  are  put  on  gas  fixtures,  the  fixture  must  be 
isolated  from  the  main  pipe,  and  the  insulator  used  for  this 
purpose  must  be  made  so  that  the  sediment  in  the  gas  will 
not  form  a  connection  over  the  insulating  material. 

Chandeliers  or  brackets  attached  to  any  ground  connec' 
tion  must  have  insulating  yokes  or  couplings  on  them. 
Individual  insulating  of  lamps  at  the  sockets  will  not  I  e 
passed  except  on  brackets  in  special  cases  that  may  be  ap- 
proved by  the  inspector. 

DYNAMO   MACHINES. 

Dynamo  machines  must  be  located  in  dry  places,  not  ex- 
posed to  flyings  or  easily  combustible  material,  and  insula- 
ted upon  wooden  foundations.  They  must  be  provided 
with  devices  capable  of  controlling  any  changes  in  the 
quantity  of  the  current  ;  and  if  these  governors  are  not 
automatic,  a  competent  person  must  be  in  attendance  near 
the  machine  whenever  it  is  in  operation. 

Each  machine  must  be  used  with  complete  wire  circuit ; 
and  connections  of  wires  with  pipes,  or  the  use  of  ground 
circuits  in  any  other  method,  are  absolutely  prohibited. 

The  whole  system  must  be  kept  insulated,  and  tested 
every  day  with  a  magneto  for  ground  connections  in  ample 
time  before  lighting,  to  remedy  faults  of  insulation,  if  they 
are  discovered  ;  and  proper  testing  apparatus  must  in  each 
case  be  provided.  This  applies  to  both  central  station  and 
isolated  plants. 

Testing  circuits  for  grounds  Vith  a  battery  and  bell  is 
not  considered  a  reliable  test. 

Preference  is  given  for  switches  constructed  with*  a  lap- 
ping connection,  so  that  no  electric  arc  can  be  formed  at 
the  switch  when  it  is  changed  ;  otherwise  the  stands  of 
switches,  where  powerful  currents  are  used,  must  be  made 
of  some  incombustible  substance  which  will  withstand  the 
heat  of  the  arc  when  the  switch  is  changed. 
MOTORS. 

Wires  for  motors  should  be  run  exactly  as  for  lamps  on 
similar  circuits.  On  low  tension  circuits  where  motors  are 
run  in  multiple,  safety  catches  must  be  used  on  each  side 
of  the  circuit. 

On  high  tension  circuits  the  same  restrictions  apply  as 
for  arc  lamps,  and  suitable  cut-outs  must  be  provided. 


64        DYNAMO  TENDERS'  HAND-BGOK. 

Motors  must  be  treated  as  dynamos  as  regards  insulation, 
flyings,  dampness,  etc. 

While  these  rules  are  intended  to  be  complete,  some  cases 
may  arise  where,  in  the  judgment  of  the  inspector,  some 
deviation  from  them  may  be  necessary  in  order  to  secure 
safety. 

RULES    FOR    RUNNING   INCANDESCENT    CIRCUITS    FROM 
ALTERNATING   MACHINES. 

Outside  wires  should  be  treated  as  arc  light  wires;  inside 
wires  the  same  as  incandescent  circuits.  Converters  on 
alternating  circuits  must  be  outside  of  buildings,  and  must 
be  placed  high  enough  from  the  roof  to  prevent  possible 
injury  to  firemen. 

RULES   TO    APPLY    TO    THE   RUNNING    OF    INCANDESCENT 
CIRCUITS   WORKED    FROM   ARC   CIRCUITS. 

The  running  of  incandescent  lights  or  systems  on  arc 
circuits  should  be  avoided;  but  wherever  this  is  unavoidable 
a  proper  device  or  distributor,  such  as  may  be  approved  by 
this  union,  must  be  provided  to  prevent  the  possibility  of 
an  excessive  arc  current  being  thrown  on  to  any  one  por- 
tion of  the  incandescent  system  ;  such  device  or  distribution 
must  have  the  approval  of  this  union  before  it  is  put  in 
operation.  It  must  remain  open  to  inspection  at  all  times, 
and  no  change  made  in  any  part  of  the  installation  after 
it  has  been  approved,  without  consent  of  this  union. 

Only  such  wire  as  has  been  approved  by  this  union 
shall  be  used  in  constructing  lines  and  circuits. 

Wires  must  be  run  in  plain  sight.  In  damp  places  they 
must  have  a  waterproof  covering. 

The  positive  wire  or  wires  must  be  kept  at  least  two  and 
a  half  inches  from  the  negative  wire  or  wires  in  running 
from  the  distributor  or  regulator  to  the  fixtures  and  lamps, 
and  return;  except  "twin  wire"  may  be  used  for  a  single 
lamp. 

No  wires  should  be  run  through  partitions,  floors  or 
walls,  without  being  incased  in  a  tube  of  hard  rubber,  por- 
celain, or  covered  with  tape.  .  Soft  rubber  tube  is  not  desir- 
able as  an  insulator. 

The  safety  fuses  must  be  so  proportioned  that  they  will 
melt  long  before  the  wire  is  heated  to  an  unsafe  degree. 

Dust  must  not  be  allowed  in  the  distributor-box  nor  any 
of  the  electrical  connections. 

The  contact  points  should  be  kept  clean,  and  care  should 
be  taken  to  insure  solid  electrical  connections  at  all  the 


SAFETY  REG ULA  TIONS.  65 

points  of  contact,  and  all  parts  must  be  kept  free  to  move 
easily. 

In  case  any  defect  should  arise  in  the  distributor  or  regu- 
lator, or  the  wiring  thereto,  it  must  be  arranged  so  as  to 
automatically  and  absolutely  shunt  off  from  the  arc  circuit 
at  once. 

In  working  distributors,  the  line  or  circuit  current  must 
be  kepfat  its  standard  amount  by  tests  made  by  ampere 
meter,  from  time  to  time.  In  no  case  must  the  amount  ex- 
ceed the  standard. 

Every  company  shall  have  a  competent  and  reliable  per- 
son to  examine,  daily,  every  distributor  and  regulator,  or 
similar  device  which  may  in  the  future  be  applied  to  arc 
circuits. 

Where  incandescent  lights  are  run  on  arc  circuits,  the 
following  named  practices  are  strictly  prohibited;: 

Fastening  or  attaching  electroliers,  or  lamps,  to  any 
gas  fixture  which  may  be  in  electrical  connection  with  the 
earth. 

The  running  of  concealed  wires  to  the  electroliers,  or 
lamps,  under  any  circumstances.  They  must  be  entirely 
open  to  view. 

The  placing  of  any  distributor  box  or  regulator,  electro- 
lier, bracket  or  lamp  in  such  a  position  that  it  may  be  con- 
nected in  any  way  with  any  other  wires,  steam  fittings,  gas 
pipes,  gas  fixtures,  etc.,  which  may  be  electrically  connected 
with  the  earth. 

The  placing  of  distributors,  electroliers,  etc.,  in  any 
damp  location,  or  in  close  proximity  to  any  metals  or  other 
conductor  of  electricity. 

The  building  or  placing  of  anything  around  the  distribu- 
tor or  regulator  so  as  to  cut  off  easy  access  to  it,  or  obstruct 
the  access  of  air  to  it. 

All  joints,  after  leaving  the  distributor  or  regulator, 
must  be  soldered,  using  acid  as  flux.  Resin  will  not  be 
approved  under  any  circumstances. 

All  new  devices  should  be  submitted  to  the  inspector  of 
the  union,  and  must  be  approved  by  him  before  permission 
can  be  given  for  their  use. 

While  these  rules  are  intended  to  be  complete,  some 
cases  may  arise  where,  in  the  judgment  of  the  inspector, 
some  deviation  from  them  may  be  necessary  in  order  to 
secure  safety. 

THE   FOLLOWING   FORM    SHOULD    BE   USED    IN    POLICIES: 

Permission  is  given  for  the  installation  and  for  the  use 


66        D  YNAMO    TENDERS'  HAND-BOOK. 

of  such  wires,  lights  and  apparatus  of  any  electric  light  or 
electric  power  system,  located  in  or  on  the  insured  premises, 
as  have  been  or  shall  be  approved  by  the  Boston  Fire  Un- 
derwriters' union. 


English  Regulations.1 

The  difficulties  that  beset  the  electrical  engineer  are 
chiefly  internal  and  invisible,  and  they  can  only  be  effectu- 
ally guarded  against  by  testing  or  probing  with  electric 
currents.  They  depend  chiefly  on  leakage,  undue  resist- 
ance in  the  conductor,  and  bad  joints,  which  lead  to  waste 
of  energy  and  the  dangerous  production  of  heat.  These 
defects  can  only  be  detected  by  measuring,  by  means  of 
special  apparatus,  the  currents  that  are  either  ordinarily, 
or  for  the  purpose  of  testing,  passed  through  the  circuit. 
Should  wires  become  perceptibly  warmed  by  the  ordinary 
current,  it  is  an  indication  that  they  are  too  small  for  the 
work  they  have  to  do,  and  that  they  should  be  replaced  by 
larger  wires.  Bare  or  exposed  conductors  should  always 
be  within  visual  inspection,  and  as  far  out  of  reach  as  pos- 
sible, since  the  accidental  falling  on  to,  or  the  thoughtless 
placing  of,  other  conducting  bodies  upon  such  conductors 
would  lead  to  short  circuiting,  and  the  consequent  sudden 
generation  of  heat,  due  to  an  increased  current,  in  conduc- 
tors not  adapted  to  carry  it  with  safety. 

The  necessity  can  not  be  too  strongly  urged  for  guarding 
against  the  presence  of  moisture,  and  the  use  of  earth  as 
part  of  the  circuit  tends  to  magnify  every  other  source  of 
difficulty  and  danger. 

The  chief  dangers  of  every  new  application  of  electricity 
arise  from  ignorance  and  inexperience  on  the  part  of  those 
who  supply  and  fit  up  the  requisite  plant. 

The  greatest  element  of  safety  is  therefore  the  employ- 
ment of  skilled  and  experienced  electricians  to  supervise 
the  work. 

I.  —  THE    DYNAMO   MACHINE. 

1.  The  dynamo  machine  should  be  fixed  in  a  dry  place. 

2.  It  should  not  be  exposed  to  dust  or  flyings. 

1  Rules  and  regulations  for  the  prevention  of  fire  risks  arising 
from  electric  lighting,  recommended  by  the  council  in  accordance 
with  the  report  of  the  committee  appointed  by  the  Society  of  Tele- 
graph Engineers  and  of  Electricians,  May  11,  1882. 


SAFETY  REGULATIONS.  67 

3.  It  should  be  kept  perfectly  clean  and  its  bearings  well 
oiled. 

4.  The  insulation  of  its  coils  and  conductors  should  be 
practically  perfect. 

5.  All  conductors  in  the  dynamo  room  should  be  firmly 
supported,  well  insulated,  conveniently  arranged  for  inspec- 
tion, and  marked  or  numbered. 

II. —  THE    WIRES. 

6.  Every  switch  or  commutator  used  for  turning  the  cur- 
rent on  or  off  should   be  constructed   so  that  when  it  is 
moved  and  left  it  can  not  permit  of  a  permanent  arc  or  of 
heating. 

7.  Every  part  of  the  circuit  should  be  so  determined  that 
the  gauge  of  wire  to  be  used  is  properly  proportioned  to 
the  currents  it  will  have  to  carry,  and  all  junctions  with  a 
smaller  conductor  should   be  fitted  with  a  suitable  safety 
fuse  or  protector,  so  that  no  portion  of  the    conductor 
should  ever  be  allowed  to  attain  a  temperature  exceeding 
150°  Fah. 

8.  Under  ordinary  circumstances,  complete  metallic  cir- 
cuit should  be  used;  the  employment  of  gas  or  water  pipes 
as  conductors,  for  the  purpose  of  completing  the  circuit, 
should  not  in  any  case  be  allowed. 

9.  Bare   wires  passing  over  the  tops  of  houses  should 
never  be  less  than  seven  feet  clear  of  any  part  of  the  roof, 
and  all  wires  crossing  thoroughfares   should  invariably  be 
high  enough  to  allow  fire  escapes  to  pass  under  them. 

10.  It  is  most  essential  that  joints  should  be  electrically 
and  mechanically  perfect  and  united  by  solder. 

11.  The  position  of  wires  when  underground  should  be 
clearly  indicated,  and  they  should  be  laid  down  so  as  to  be 
easily  inspected  and  repaired. 

12.  All  wires  used  for  indoor  purposes  should  be  effi- 
ciently insulated,  either  by  being  covered  throughout  witn 
some  insulating  medium,  or,  if  bare,  by  resting  on  insu- 
lated supports. 

13.  When  these  wires  pass  through  roofs,  floors,  walls, 
or  partitions,  or  where  they  cross  or  are  liable  to  cross  me- 
tallic masses,   like  iron    girders  or  pipes,  they  should  be 
thoroughly  protected  by  suitable  additional  covering;  and 
where  they  are  liable  to  abrasion  from  any  cause,  or  to  the 
depredations  of  rats  or  mice,  they  should    be  efficiently 
encased  in  some  hard  material. 

14.  Where  indoor  wires  are  put  out  of  sight,  as  beneath 


68        DYNAMO    TENDERS'  HAND-BOOK. 

flooring,  they  should   be  thoroughly  protected  from  me- 
chanical injury,  and  their  position  should  be  indicated. 

N.  B.  —  The  value  of  frequently  testing  the  apparatus 
and  circuits  can  not  be  too  strongly  urged.  The  escape  of 
electricity  can  not  be  detected  by  the  sense  of  smell,  as  can 
gas,  but  it  can  be  detected  by  apparatus  far  more  certain 
and  delicate.  Leakage  not  only  means  waste,  but  in  the 
presence  of  moisture  it  means  destruction  of  the  conductor 
and  its  insulating  covering,  by  electric  action. 

in. —  LAMPS. 

15.  Arc  lamps  should  always  be  guarded  by  proper  lan- 
terns, to  prevent  danger  from  falling  incandescent  pieces 
of  carbon,  and  from  ascending  sparks.    Their  globes  should 
be  protected  with  wire  netting. 

1 6.  The  lanterns,  and  all  parts  which  are  to  be  handled, 
should  be  insulated  from  the  circuit. 

IV. —  DANGER  TO   PERSON. 

17.  Where  bare  wire  out  of  doors  rests  on  insulating 
supports,  it  should  be  coated  with  insulating  material,  such 
as  india-rubber  tape  or  tube,  for  at  least  two  feet  on  each 
side  of  the  support. 

1 8.  To  secure  persons  from  danger  inside  buildings,  it  is 
essential   so  to   arrange  and    protect   the  conductors   and 
fittings  that  no  one  can  be  exposed  to  the  shock  of  alterna- 
ting currents  of  a  mean  electromotive  force  exceeding  100 
volts,  or  to  continuous  currents  of  200  volts. 

19.  If  the  difference   of    potential    within   any   house 
exceeds  200  volts,  the   house  should   be  provided   with  a 
switch,  so  arranged  that  the  supply  of  electricity  can  be  at 
once  cut  off. 


Abstract  of  the  Chicago   Electric  Light 
Laws. 

No  plant  shall  be  run  without  a  certificate  of  inspection 
from  the  superintendent  of  city  telegraph.  No  wire  of  less 
conductivity  than  number  6  B.  &  S.  copper  shall  be  used  for 
arc  lights.  The  conductors  shall  be  fire-proof  coated  and 
well  insulated,  run  eight  inches  apart  on  insulators  along 
walls  and  ceilings,  well  insulated  through  walls,  floors,  etc. 
Lamps  must  have  globes  and  be  protected  from  accidental 
contact,  and  where  light,  inflammable  matters  are  near,  the 
globes  must  have  wire  screen  spark  protectors.  Where 


y  j^RGUI^-rt  j-  /L/Ar*?.  69 

dynamos  are  open  to' the  public  they  must  be  protected  by 
rail  or  screen.  Incandescent  circuits  may  be  run  in  mold- 
ings, but  in  all  cases  soft  fusible  metal  strips  of  proper  size 
must  be  placed  at  each  branching  of  the  wire. 

The  insulation  resistance  required  is  one  megohm  (i,ooo,~ 
ooo  ohms),  and  the  inspection  fee  is  $i  per  horse  power 
used — one  ordinary  arc  light  being  allowed  per  horse  power, 
or  ten  16  candle  power  incandescent  lamps. 

The  plant  cannot  be  legally  altered  after  inspection,  ex- 
cept by  first  notifying  the  city  electrician.  While  the  plant 
remains  in  the  same  condition  as  at  the  date  of  the  certifi- 
cate, that  document  is  valid. 

Violation  of  any  one  of  the  above  requirements  subjects 
the  party  so  transgressing  to  a  fine  of  from  $50  to  $100  for 
each  day  the  infraction  is  continued. 


Overhead    Conductors    for   Electric 
Light  and  Power.1 

I.  No  two  lines  of  poles  bearing   conductors   of   a   like 
class  shall  be  erected  on  any  street  or  avenue. 

II.  No  two  lines  of  poles  shall  be   erected   on   the  same 
side  of  any  street  or  avenue. 

III.  Poles  shall  be  set  in  the  sidewalk  twelve  inches  from 
the  outside  of  curb,  and  no   pole  shall  be  placed  within  ten 
feet  of  ^ny  lamp  post  or  other  pole,  except  at  street  corners 
where  necessary  in  order  to   support  wires  running   on  the 
cross  street. 

IV.  All  poles  now  standing,  or  to  be  hereafter  erected, 
shall  be  branded  or  stamped  with  the  initials  of  the  company 
owning  them,  at  a  point   not   less   than  five  nor  mere  than 
seven  feet  from  the  street  surface;  and   when  a  pole  is  oc- 
cupied by  wires  belonging  to  more  than  one  company,  each 
group  of  cross-arms,  or  where  necessary   the   support  of  a 
single  wire  of   different  ownership,  must   be   distinguished 
by  some  characteristic  paint,  mark  or  fastening. 

V0  Electric  light  lamp  posts  shall  be  in  accordance  with 
the  plan  adopted  by  the  board. 

VI.  All  poles  erected  for  the  purpose  of  carrying  lines  of 
more  than  two  electric  light  or  power  wires  shall  be  at  least 
forty-five  feet  high,  uniform  in  size,  straight,  and  painted 
from  top  to  bottom — a  very  dark  color  from  the  sidewalk 

1  Rules  and  Regulations  of  the  Board  of  Electrical  Control,  New 
York. 


70       DYNAMO    TENDERS'  HAND-BOOK. 

to  a  point   eight   feet   high,  and  a  dark  green  color  above 
that. 

VII.  All  poles  for  carrying  not   more  than  two  electric 
light  wires  shall  be  twenty-five  feet  high,  straight,    uniform 
in  size,  and  painted  from  top   to  bottom — a  very  dark  color 
from  the  side  walk  to  a   point   eight   feet  high,  and  a  dark 
green  color  above  that. 

VIII.  Cross-arms   shall  be   uniform  in  length,  strength- 
ened by  braces,  and  painted  the   same   color   as  the  poles; 
the  cross-arms  of   each  company    being   distinguished   by 
some  characteristic  mark. 

IX.  Each  line  of   poles  must  be  run  on  one  side  of   the 
street  only,  except  when  absolutely  necessary  to   change  to 
the  other  side;  but  this  may  only  be  done  by  the  permission 
of  the  board  or  of  its  engineer  or  expert. 

X.  Electric  light  conductors   must   not   be  placed  upon 
fixtures  erected  or  maintained  for   supporting  wires   of  the 
other  class,  namely  those   for  signalling,  except  by  permis- 
sion of  the  board. 

XI.  Poles  shall  be  uniformly  spaced,  and   about  sixty  to 
the  mile.     This  requires  on   the   short   city  blocks  of   two 
hundred  and   sixty    feet,  alternately  three  and  two  poles  to 
the  block. 

XII.  All  conductors  shall  be   secured   to  insulating  fast- 
enings, and   covered   with   an  insulation   which   is  water- 
proof on   the   outside,  and   not   easily   worn   by  abrasion. 
Whenever  the  insulation  becomes  impaired   it   must  be  re- 
newed immediately. 

XIII.  No  wire  shall  be   stretched   within   four  inches  of 
any  pole,  building  or   other   object,  without  being  attached 
to  it  and  insulated  therefrom. 

XIV.  Every  wire  must  be  distinguished   by  a   number 
plainly  marked  on  each  cross-arm  under  the  insulator. 

XV.  No  unused  loops   from   electric   light  circuits  shall 
be  allowed  to  remain  after  lamps  are  taken  away,  except  in 
cases  where  it  is  positively  known  that   the  lamp  will  be  re- 
quired again  within  three   months,  and   where   there   is  no 
underground  conduit  for  that  class  of  circuits. 

XVI.  All   arc   lamps   must  be  so  placed   as   to  leave  a 
space  underneath  of  nine  (9)   feet  clear   between  lamp  and 
sidewalk. 

XVII.  All  wires  must  be  stretched   tightly  and  fastened 
to  glass  or  porcelain   insulators,    approved   by   the   expert, 
with  a  strap  of  the  same  kind  of  wire. 

XVIIL  All  connections  with  lines   of  electric  light  con- 


SAFETY  REGULATIONS.  71 

ductors  shall  be  made  at  right  angles  to  the  same ;  and  con- 
nections to  buildings  shall  be  run  straight  across  to  the 
building,  and  then  down  the  front  of  the  building. 

XIX.  All   joints  must  be   as   well   insulated  as  the  con- 
ductors, and  the  insulation  of  joints  must  be  maintained. 

XX.  Every  line    entering  a   building  shall  be  controlled 
by  a  cut-off  placed  near  the  entrance,  in  sight,  and  easily  ac- 
cessible. 

XXI.  No  wires  shall   hang  within   twenty   feet   of   the 
pavement  at  the  lowest  point  of  sag  between  supports. 

XXII.  In  the  construction  of   lines   the   insulation  to  be 
used  must  be  approved  by  the  expert   of   the  board  in  writ- 
ing, and  the  insulation  resistance  must  be  maintained  in  ac- 
cordance with  a  standard  to  be  not  less  than  1-80  megohm 
per  mile  per  hundred  volts.     And   under  no  circumstances 
shall  underwriters'  wire  be  used. 

XXIII.  All   circuits   must    be   tested   every   hour,   and 
when  a  ground  comes  on,  effort  must  be  made  to  remove  it 
at  once.     Failing  in  this,  the  current  must  be  discontinued 
until  the  insulation  is  restored. 

XXIV.  The  insulation  must  be  preserved  throughout  the 
entire  circuit,  and  if  any  portion  of   a   lamp  or   fixture  is  a 
part  of  the  circuit  and  can  be  touched,  it  must  be  insulated. 

XXV.  All  conductors  shall  have   a   resistance  uniformly 
distributed  of  not  more  than  30  ohms  per  mile  per  ampere, 
and  proportionately  less  for  heavier  currents. 

XXVI.*  All  existing  regulations  of  the  local  authorities 
in  regard  to  the  placing  of  poles  and  the  stiinging  of  wires  are 
to  continue  in  force,  except  when  in  conflict  with  these  rules; 
and  the  rules  and  regulations  of  the  New  York  Board  of 
Fire  Underwriters  must  be  strictly  observed. 

X  XVII.  The  violation  of  any  of  the  rules  and  regulations 
of  the  board  shall  operate  ipso  facto  as  a  revocation  of  the 
permit  held  by  the  company  or  person  guilty  of  such  vio- 
lation. 

XXVIII.  Whenever  hereafter  any  company  shall  be  per- 
mitted by  this  board,  or  its  successors,  to  erect  posts  or  poles, 
or  other  fixtures  bearing  lamps  or  other  devices,  for  the 
purpose  of  lighting  by  electricity  the  streets,  avenues,  high- 
ways, parks  or  public  places  of  the  city,  the  said  permission 
shall  be  granted  only  subject  to  the  following  provisions, 
and  the  same  is  hereby  expressly  made  a  condition  of  such 
permits.  At  any  time  when,  by  action  of  the  city  author- 
ities, the  contract  for  lighting  any  such  street  or  other  public 
place  shall  be  given  to  another  company,  the  company 


72       DYNAMO    TENDERS'  HAND-BOOK. 

erecting  said  lamp  posts  shall,  on  tender  of  the  first  cost 
thereof,  yield  possession  and  ownership  of  the  same  to  the 
said  other  company  obtaining  the  new  contract,  except  in 
cases  where  the  company  owning  the  lamp  posts  prefers  to 
remove  them. 

XXIX.  All   broken   and   "dead"   wires,   and  all  wires, 
poles  and  fixtures  not  actually  in  use — subject  to  Rule  XV 
— must  be  removed  from  the  streets,  avenues  and  highways 
of  the  city.     When  an  old  pole   is   taken    down  it  must  be 
removed  from  the  streets  the  same  day.     New   poles  must 
not  be  brought  upon  any  street    more  than  two  days  in  ad- 
vance of   their  erection.     Any  pole   that   shall   lie  on  any 
street  more  than  two  days  shall  be   removed  by  the  Bureau 
of  Incumbrances  of  the  Department  of  Public  Works,  at  the 
expense  of  the  party  owning  it. 

XXX.  From  and   after   the   first  of  January,    1889,  no 
company  shall  do  business  of   arc   electric    lighting   in  the 
city  of  New  York  without  a  certificate  of  the  board,  granted 
on  the  recommendation  and   after  inspection  by  the  expert 
of  the  board,  to  the  effect  that  its  lines  comply  with  all  the 
rules  and  regulations  of  •  the  board,  and   that  its  plant  is  in 
proper  condition  for  the  doing  of   its  business.     The  force 
of  the  certificate  to  continue   until   changes   are   made,  of 
which  the  board  must  be  notified  and  approve,  or  so  long  as 
the  plant  and  conductors   remain   in  the  same  condition  as 
when  inspected. 

XXXI.  Every  lineman  must  wear  a  badge  in  a  conspic- 
uous place,  giving  his  number  and  the  name  of  the  company 
by  whom  he  is  employed. 

XXXII.  All  permits  of  the  board  for  overhead  wires  and 
fixtures  are  granted   only   pending  the  providing  of  under- 
ground accommodations  in  the  neighborhood  of   the   street 
or  avenue  for  which  the  permit  is  granted. 

XXXIII.  Any  member  or  officer  of  the  board,  and  every 
inspector  employed  by  it,  as  well  as  every  member   of   the 
police  force  of  the  city,  shall  be  entitled  to  examine  permits 
under  which  work  of  any  kind  is  being  done. 

XXXIV.  No  permit  shall  be   granted  for  the  erection  of 
any  overhead  structure  nor  for  the   renewing   of   any  lines 
already  existing  in  any  street,  avenue  or  highway  in  which 
underground  accommodations  for  the  service  have  been  pro- 
vided, or  are  being  provided. 

XXXV.  Every  line,  pole,  fixture,  etc.,   must  be  kept  in 
thorough  order,  repair,  and  conformity  with  these  rules  and 
specifications,    upon   penalty   of   forfeiture  of   all   permits 
granted  to  the  owner  by  this  board. 


SAFETY  REGULATIONS.  73 

But  the  general  permit  under  which  these  repairs  are  to 
be  made  does  not  cover  the  erection  in  any  street,  avenue  or 
highway  of  any  new  poles  or  other  similar  fixtures,  and  has 
absolutely  no  reference  whatever  to  lines  which  have  been 
ordered  underground  by  the  board,  and  which  the  mayor 
has  been  requested  to  remove. 

In  the  case  of  such  lines,  where  notice  has  been  given 
that  underground  accommodations  have  been  provided,  and 
the  ninety  days  of  notice  required  by  law  have  elapsed,  and 
the  mayor  has  been  requested  to  remove  the  same,  com- 
panies owning  or  operating  said  lines  are  not  authorized  to 
make  any  repairs  or  connections  or  to  go  upon  the  poles 
bearing  such  lines  for  any  purpose  whatever,  except  to 
remove  the  said  lines  of  electrical  conductors  in  conformity 
with  the  directions  of  the  board. 

Any  deviation  from  this  rule  requires  a  resolution  passed 
at  a  regular  meeting  of  the  board,  attested  by  the  secretary. 

XXXVI.  Every  company  or  person  erecting  poles,  wires 
or  fixtures  must  make  and  leave,  at  least  once  each  week,  at 
the  office  of  the  board,  such  records  of  the  fixtures,  etc., 
which  they  are  erecting,  and  of 'all  of  the  same  that  they  have 
in  use,  as  are  required  by  the  engineer  and  the  electrical 
expert  of  the  board,  and  in  such  form  as  shall  be  prescribed 
by  them. 

XXXVII.  The  companies  or  persons  owning  or  control- 
ling poles  in  any  street  or  avenue,  erected  under  permits  of 
this  board  or  the  Board  of  Electrical  Subways,  shall  allow 
the  same  to  be  used  by  other  companies  or  persons  operat- 
ing conductors  for  similar  electrical  service  when  author- 
ized so  to  do  by  the  board,  on  tender  of  proper  compensa- 
tion, to  be  determined  by  agreement  between   the  parties 
interested.     In  default  of  such  an  agreement  the  amount  of 
such  compensation  shall  be  determined  by  the  board.  This 
rule  imports  a  contract  on  the  part  of  each  company  or  per- 
son owning  or  controlling  the  poles  on  any  street  or  avenue, 
not  only  with  the  board  but  also  with  each  company  or 
person  who  shall  under  its  terms  be  qualified  to  demand  the 
privileges  it  confers,  to  permit  this  joint  use  of  poles. 

And  in  accepting  any  permit  the  applicant  thereby  binds 
himself  to  this  agreement. 


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Lamp  Lighting  Schedule— Moonlight 
System  for  1  89 1 , 

JANUARY. 


Day  of  Month. 

Light. 

Day 
of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
2       

H.  M. 
5.  10  P.M. 
«>   IO     " 

I  
3  

H.  M. 
II.  50  P.  M. 
12  5O  A  M. 

H.  M. 
6.40 

7  4O 

-7 

c    10     " 

4..  . 

I   C.O     " 

8  4O 

A      , 

C..2O     " 

5  

a  OO     " 

Q  4O 

*>  2O     " 

6  

4  oo   ' 

10  40 

6 

K    2O      " 

7.  . 

5IO     " 

1  1   5O 

7      

C.    2O      " 

8   

6  20    " 

13  oo 

8  

5.2O      " 

Q.  . 

6  20    " 

I'l  OO 

C   2O     " 

10  

6  20    ** 

13  oo 

10  

5.2O     *' 

II  

6.  20    " 

1^  OO 

ii 

5   2O     " 

12  

6  20    " 

13  °o 

12  

5.2O     *' 

13  

6  20    " 

1^  OO 

M 

C.2O    " 

14  

6  20    •' 

I-i  OO 

14.    . 

Q.OO     " 

15    

6  20    " 

Q  20 

TC 

IO.IO     ' 

16   

6  20     " 

8  10 

16  

I  I  .  2O     " 

) 

17 

17.  . 

6  20     " 

[  7.00 

18  

IQ 

12.30  A.M. 
I  4O     " 

18  

IO.  . 

6.20     " 

6  20    " 

5.50 

4.4O 

2O 

2.40     " 

20  

6  20    " 

3.40 

21       « 

3^O     " 

21    

6  20     " 

2  ^O 

22     ,. 

4..4O     " 

22  

6.  20    *' 

1.40 

2^ 

No  light. 

23  

No  light. 

o.oo 

2/1 

Nc  light 

24  

No  light. 

o.oo 

2s  

No  li^ht. 

25  

No  light. 

*  o.oo 

26  

27    . 

5.40P.M. 

C    AQ      <( 

26....... 

27.  . 

7.50P.M. 
8  co    " 

2.10 
•J.io 

28       

c  4.0     " 

28  

Q.4O     " 

4.00 

2Q 

5/1O     " 

2Q 

IO  4O    '* 

5.00 

riQ 

C    CO      " 

30  

II.4O     ' 

5.50 

•U  

s.*.o   4< 

Feb.  i.. 

12.  40  A.M. 

6.50 

Total  number  of  hours, 


216.00 


The  foregoing  schedule  was  calculated  on  the  following  basis: 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  One  hour  after  moonrise  and  one  hour  before  sunrise. 

75 


76       DYNAMO    TENDERS'  HAND-BOOK. 


FEBRUARY. 


Day  of  Month. 

Light. 

Day 
of  Month. 

Extinguish. 

Number  of 
Hours. 

I.  

2 

H.    M. 

5.501'.  M. 
Sen     " 

2  

q 

H.  M. 
I  50  A.  M. 
2  c,O     " 

H.   M. 

8.00 
Q.OO 

C     CQ        " 

4  .  

4  OO     " 

IO.  IO 

Sen     '  ' 

c    10     " 

II  .20 

r 

C     CO        " 

5.     .... 

6   

6.IO     " 

12.  2O 

6 

5CQ       *  ' 

7 

6  oo    " 

12  .  IO 

6  oo    ' 

8  

6  oo    " 

12  .OO 

8         

6  oo    " 

Q.  . 

6.00    " 

12.  OO 

6  oo    " 

10  

6  oo    " 

12    OO 

jO 

6  oo    ' 

II  

6  oo    " 

I2.OO 

ii   

6  oo    " 

12  

6.00    " 

12.  OO 

12 

Q  IO      " 

ia  .  . 

6.00    " 

8.50 

I  a     . 

IO.2O     ' 

14  

6.00    " 

7.40 

IJ. 

II  30     " 

1  5  ....... 

5.50    " 

j-      6.20 

16  

17 

12.40  A.  M. 
I  4.O      t( 

16  

17.  . 

5-50    " 
^.50    ' 

5.10 

4.  10 

18 

2  dO     '  ' 

18 

C    CQ       " 

3-  IO 

IQ 

a.  dO     " 

IQ. 

g.gO      " 

2.  IO 

2O 

4  2O     " 

2O 

C    CQ       " 

1  .  30 

21       .  . 

C,  OO      " 

21  

5.50       " 

o.  50 

22                       . 

No  light 

22            ... 

No  light 

o.oo 

27 

No  light 

2^    . 

No  light. 

o.oo 

24 

No  light. 

24  

No  light. 

0.00 

25  
26    

6.  20  P.  M. 

6.  20    " 

25  
26  

8.40P.  M. 
9.40    " 

2.  2O 

3.20 

27 

6  20    " 

27  

10.40    " 

4.20 

28.. 

6.  20    " 

28  

11.40    " 

5.20 

Total  number  of  hours, 


178.10 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


LAMP  LIGHTING  SCHEDULE. 


77 


MARCH. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

fx  umber  of 
Hours. 

I  
2  

H.  M. 
6.  20  P.  M. 

6  20    " 

2  

a.  . 

H.  M. 
I2.4O  A.M. 
I   CO    " 

H.  M. 
6.20 

7.  3O 

Q 

6  20     " 

3OO     " 

8  40 

4     

6  20    " 

c  .  . 

4  OO     " 

9  .40 

c 

6  30    '  ' 

6 

5  oo    " 

10  30 

6  

6  10    " 

7  . 

C     -7Q       " 

II    OO 

7 

6  30    " 

8    .. 

c  2O     " 

10  50 

8    .... 

6  30    " 

c  2O     " 

10.  50 

Q  .  . 

6.30    ' 

9.  . 
10  

5.2O     " 

IO.  ^O 

10   

6  30    " 

II  

^  2O     " 

10.  50 

II  

6.30    ' 

12  

5.2O     " 

10.  50 

I  ^ 

6.30    " 

13  

c;  20   " 

10.  50 

I  -3 

6  30    " 

14 

c   10     " 

10  40 

14    ... 

IO.2O     i4 

1C.  . 

^  10   " 

6.  ^o 

I  ^     . 

1  1  10    '  ' 

16  

16  

c,  10    " 

1  5.40 

17   
18    

12.30A.M. 
I.3O     " 

17  
18  

5.10  •' 

*>   IO     " 

4.40 

•7.4.0 

in 

2  2O     " 

10.  . 

c   10     " 

2    ^O 

2O    

3.OO     " 

20  

5  OO     " 

2    OO 

21    .  . 

3  4O     " 

21       .... 

c  no     " 

I    20 

22    

4.IO     " 

22  

^  .  OO     '  * 

o.  ^o 

27 

No  light 

23.  . 

No  light 

o.  oo 

24  

No  light 

24  

No  light. 

o.oo 

25  

No  light. 

25  

No  light. 

o.oo 

26  

6.50P.M. 

26  

8.  30  P.  M. 

1.40 

27 

6.50    " 

27  

Q.3O     " 

2.40 

28 

6.50    " 

28  

10.40    ' 

3.  50 

2Q 

6.50    " 

2Q  

1  1  .  40    " 

4.50 

or) 

6.  co    " 

31  

I2.5O  A.M. 

6.00 

31.  . 

6.50    " 

April  i.  .  . 

1.50  " 

7.00 

Total  number  of  hours, 


183. 10 


The  foregoing  schedule  was  calculated  on  the  following  basis : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


DYNAMO    TENDERS'   HAND-BOOK. 


APRIL. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I          .          ... 

H.  M. 

6  50  r  M 

2 

H.  M. 
2  50  A  M 

H.   M. 

8  oo 

2  

7  OO     " 

o   en      '  ' 

8  50 

<\ 

7  oo    " 

4  on      " 

9Or\ 

A      . 

7  .  OO     '  ' 

e 

4J.O      '  ' 

•  JU 
Q  4O 

C   .  . 

7  OO      " 

6  

4.  4O      " 

94O 

6    

7  OO     ' 

7 

4^O     '  ' 

90Q 

8  

7  OO     <c 

A    T.Q      il 

9-20 

7  OO      '  ' 

JO  

4  on      " 

9    Of) 

9.  . 
io    

7  OO      <: 

II  

4^O      '  ' 

9  on 

ii  

7  oo    " 

12  

d.^O      " 

Q  ^O 

12        

IO  2O      " 

M, 

4.  ^O      '  ' 

6   IO 

1-2   .   . 

1  1  20     '  ' 

) 

14  

IJ.  

4.2O      " 

f     5-00 

15  
16  

12.20  A.M. 
I  OO      " 

15      

16   

4.20      " 
4.2O      " 

4.00 
^  20 

17  .  . 

I   4O      " 

I  7. 

4  20    " 

2  4O 

18  

2.IO      " 

18  

4.20    4< 

2   IO 

IQ 

2  4O     <4 

IO    . 

4  2O     " 

I  jo 

2O  

I  OO     " 

20  

4.IO      " 

I.  IO 

21  

3.  2O     *' 

21  

4.IO     " 

O.5O 

22     

No  light. 

22  

No  light. 

O  OO 

21>  .  . 

No  light. 

23  . 

No  light. 

o.oo 

2/1 

No  light. 

24..  . 

No  light. 

O  OO 

25  

26 

7.20  P.  M. 

7  2O     " 

25  
26  

9.  30  p.  M. 
10.40    " 

2.10 
3-2O 

27  .  . 

7.  2O     " 

27.  ...... 

11.50    " 

4.30 

28 

7  2O     " 

2Q    . 

12.  co  A.  M. 

5.30 

2Q  .  . 

7.2O     ' 

30    

I.4O      " 

6.  20 

3°  

7.2O     " 

May  I  ... 

2.3O      " 

7.10 

Total  number  of  hours, 


149.10 


The  foregoing  schedule  was. calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset,  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


LAMP  LIGHTING  SCHEDULE, 


MAY. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
2  

H.    M. 
7-3OP.  M 
7-20     " 

2  

3  

H.    M. 
3.  10  A.M. 

•2.    CO      " 

H.    M. 
7.40 

8.  20 

•7 

7  -3O     " 

-2     CQ      " 

8  20 

7.3O    *' 

4.  . 
5  

•2.    CQ      " 

8.  20 

_ 

7  ao     " 

6  

•2    tO      " 

8  20 

6  

7-20     " 

7  

Q    CQ      " 

8.  20 

7     . 

7-20     " 

8. 

O     CQ      " 

8  20 

8  

7-20     '  ' 

Q    .... 

•2.  CQ      " 

8.  20 

7-20    " 

IO.  ... 

q   CQ     " 

8  20 

9. 
10  

7.4O    " 

II  ....... 

•2.  CO      " 

8.  10 

ii             ... 

7  40    " 

12     ... 

o   CQ     " 

8.  10 

12  

IT.OO    " 

13  

-2    CQ      " 

4  .  SO 

IT     . 

1  1  dO     " 

^4 

T    1 

3   dO     " 

[  4.00 

1  c     . 

12   IOA    M. 

I  c 

3J.O     " 

0  .  -2Q 

16 

1  2  40     '  ' 

16 

•2    4O       '  ' 

3OO 

17     . 

I    IO    " 

17  .. 

o    IQ     *' 

2    IO 

18 

I  qn    " 

18 

q  J.O     '  ' 

2    IO 

IQ 

I   ^O    " 

IQ.  . 

•2    4O      " 

I    SO 

2O 

2   IO     '  ' 

2O 

•2     JO       " 

I    ^O 

21  .... 

No  lio-ht 

21  

No  light 

o  oo 

22 

No  light 

22     .. 

No  light 

o  oo 

23          .-  
2d 

No  light. 

7  CO  P    M 

23  
2A 

No  light. 
9  40  p  M 

0.00 
I  .  SO 

2S  .  . 

7  50   " 

2Z     . 

10.40    " 

*     2.  50 

26       

7  CQ    " 

26        .... 

11.40    " 

•2  .  CO 

27 

7  en    *' 

27 

1  2  30  A    M 

4  do 

28 

7  ^O    " 

2Q.  . 

I.  IO     " 

s  .  20 

2Q    . 

7.50    " 

30  

I.5O     " 

6.00 

-2Q 

7  50   " 

^1  .  . 

2.  2O     " 

6  30 

•U.    . 

7.^0    " 

Tune  i  .  . 

2..  SO    " 

7.00 

Total  number  of  hours, 


152.00 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-halt  hour  after  sunset  and  one  hour  before  moonstt. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


DYNAMO  TENDERS'  HANDBOOK. 


JUNE. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
2    

H.  M. 
7.  50  P.  M. 

8  oo    " 

2  

a  .  . 

H.  M. 

3.  10  A.M. 
a   -30     " 

H.  M. 
7.20 
7   QO 

8  oo    " 

1  ar>     " 

7O() 

A 

8  oo    " 

c 

Q    ^o     " 

•     7   IO 

e 

8.00    " 

6  

o   CQ     " 

7  ^O 

6 

8  oo    " 

7 

q    7o     " 

7  ^O 

7     ... 

8  oo    " 

8  

0     OQ       '  ' 

7  QO 

8  

8  oo    " 

o.  . 

^   ^O     " 

7    'JQ 

Q 

8  oo    " 

IO       .... 

T     -2Q       '  ' 

7    -7Q 

10  

IO.IO     " 

1  1    

a  -20     " 

e  20 

II             

10  40    ' 

12       ... 

a    -2Q       '  ' 

J.   ^O 

12        

1  1.  IO     " 

J-2  .   . 

^  ^O     " 

1  20 

T*i 

i  i  30    " 

a   -3Q     " 

J.  OO 

Id 

11.50    " 

) 

1C     . 

15  

3-3°    " 

•    3-40 

16            

I2.IO  A  M. 

16  

o   QO     " 

3  °o 

I  7 

12  JO     ' 

I  7 

•i   ^o     '  ' 

o   co 

18     .  . 

I  OO     " 

18  

a   ^o     " 

2   ^O 

10  . 

1  .  3O     " 

IQ.  . 

3.30    ' 

2  CO 

20 

No  light 

2O    

No  lioht 

O  OO 

21       

No  light. 

21  

No  light. 

O  OO 

22 

No  light 

22             ... 

No  light 

o  oo 

27 

8   IO  P.  M. 

«2^.  . 

10.30  P.  M. 

2  2O 

2/1 

8  10    " 

24. 

II   IO     " 

^  OO 

OK. 

8  10    " 

25  

imo  " 

3  40 

26 

8  10    " 

27    . 

12  2OA  M 

4  10 

27 

8  10    " 

28  

12  50     " 

4.40 

28 

8  10    " 

2Q 

I  2O     " 

^    IO 

2Q 

8  10    " 

^O.  . 

I  40     " 

5.30 

^O.  . 

8.10    " 

July  i.  . 

2.IO     " 

6  oo 

Total  number  of  hours, 


134.40 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


LAMP  LIGHTING  SCHEDULE. 


JULY. 


Day  of  Month. 

Light. 

Day 
of  Month. 

Extinguish. 

Number  of 
Hours. 

I  

H.  M. 
8.  10  P.M. 
8.10     " 

8.00    " 
8.00   " 
8.00    " 
8.00    " 
8.00    " 
8.00    " 
8.00    " 
9.30    " 

IO.OO     *' 
10.20     " 
10.40     " 
11.00     " 

11.30    " 

12.00   M. 

2  

H.  M. 
2.40A.M. 
3.20     " 

3.30     " 
3-30     ' 

3  40    ' 
3.40    ' 
3.40    ' 
3-40    ' 
3-40    ' 
3.40    ' 
3.40    ' 
3.40    " 
3-40    " 
340    ' 
3-40    " 

3.40    " 
3.40    ' 
3-40    " 
No  light. 
No  light. 
No  light. 

IO.2OP.  M. 

10.50    " 
1  1.  20    ' 
11.50    " 

12.  10  A.M. 
12.40     ' 
1.20     " 
1.50     " 
2.dO     " 

H.  M. 
6.30 
7.10 
7-30 
7.30 
7.40 
7.40 
7-40 
7.40 
7.40 

6.10 
5.40 
5.20 
500 
4.40 
4.10 

|    3.40 
3.10 

2.20 
0.00 
O.OO 
0.00 
2.30 
3.00 
3-30 
4.00 
4.20 
4.50 
5-30 

6.00 
6.e.o 

3  

4  
5  

4  o  

c 

6..    .. 

6   

7  

7 

8     ... 

9  

10     .    . 

10  

ii  

II  

12 

12  

13  

1-2 

14  

15  

1C 

16 

16  
17  

17    . 

18   

IQ    . 

12.  3O  A.M. 
1.20     " 

No  light. 
No  light. 
No  light. 
7.  50  P.M. 
7.50    ' 
7-50    ' 
7-50    " 
7.50    ' 
7.50    ' 
7-50    " 
7-50    ' 

7.C.O     " 

18  

IQ. 

2O  

2O  

21  

21  . 

22  

22  

23  

2J. 

23  
24  

25  

25.  . 

26       

26 

27.  

28.        . 

28  

2Q 

29  

30  

3O  

-2T  . 

'U.  . 

Auo\    I.  . 

Total  number  of  hours, 


157.40 


The  foregoing  schedule  was  calculated  on  the  following  basis: 
Light  one-half  hour  after  sunset   and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


82        DYNAMO    TENDERS*  HAND-BOOK. 


AUGUST. 


Day  of  Month. 

Light. 

Day 
of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
.    2  

H.  M. 
7.50P.  M. 
7.  CQ     " 

2  

-2  .  . 

H.   M. 
3.  30  A.  M. 

4  oo    " 

H.  M. 

7.40 
8  10 

3  

7.40     ' 

4  

4..OO      " 

8  20 

4.  .  . 

7.4O     " 

e 

4  oo    ' 

8  20 

5  

7.40     " 

6  

4..  CO     " 

8  20 

6     

7  4O     " 

7.  . 

4  oo    *' 

8  20 

7  4O      (t 

8 

4  oo    (t 

8  20 

8 

8  20      " 

4  oo    '  ' 

7  4O 

Q  .  . 

8.40     " 

10  

4  IO     " 

7  3O 

JO  

q.OO      " 

ii  

4.10     " 

7.  10 

II  

Q    aO        " 

12  

4.  IO     " 

6  40 

J2     

Q    CO        " 

iq 

4.  IO     " 

6  20 

1-7       . 

IO  3O      " 

IJ, 

A    IQ      " 

e  AQ 

14.  .  . 

II   IO      " 

1C   .  . 

ie  .  . 

4.  IO      " 

|      5.00 

16  

17  ... 

12.  00  A.M. 
I  OO      " 

16  

17 

4.10      ' 

4  10    " 

4.10 

•3  10 

18  

No  light. 

18  

No  light 

o.oo 

IQ  . 

No  light 

IQ.  . 

No  light 

o.oo 

20  

No  light. 

20    ..... 

No  light. 

o  oo 

21  
22  

7.  20  P.  M. 
7  2O     " 

21  
22  

9.2O  P.  M. 
Q  en     " 

2.00 
2  3O 

23  

7.2O     " 

23  

IO.  IO     ' 

2.5O 

24  .  . 

7  2O     " 

24..  . 

10  40    " 

3  20 

2C  .  . 

7  IO     " 

2C     . 

II   IO     " 

4  OO 

26     

7  IO     " 

26  

11.  ^O     " 

4  4° 

27  

7.IO     ' 

28  

12.  40  A.M. 

5.30 

28  

7  IO     " 

2Q  .  . 

I.^O     " 

6.  20 

2Q 

7  10     " 

T.Q     . 

2  ^O     il 

7  20 

30  

7.IO     ' 

31  

3.2O     " 

8.  TO 

31  .' 

7.oo    " 

Sept.  I.  . 

4.  30     '  : 

Q.30 

Total  number  of  hours, 


167.00 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise 


LAMP  LIGHTING  SCHEDULE. 


SEPTEMBER. 


Day  of  Month, 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I    
2    

H.    M. 

7.  cor.  M. 

7.OO    " 

2.  

a  .  . 

H.    M. 

4.30A.M. 

43O     '  ' 

H.    M. 

9-30 

91Q 

a 

7  OO     " 

J.   ^O     '* 

90Q 

7  oo   " 

S 

d    ^O      " 

9qo 

4.  ... 

c 

7  OO    " 

6 

4OO     " 

9  an 

6  

7  OO     " 

d    ^O      " 

9  an 

7  3O     " 

8 

4qo    " 

Q  OO 

8  

8  oo   " 

A    7O     '* 

8  30 

8  ^o   " 

9.  .  . 

10 

4qo    '  ' 

8  OO 

9. 
10   

Q.OO     " 

ii  

d  4.O    " 

7  J.O 

ii    ... 

Q  ^O     " 

12       ... 

4J.O    '  ' 

6  50 

12  

10.40    '' 

I*.  , 

A    J.O      " 

6  oo 

1-3       . 

II   ^O     '  4 

) 

14  

14    

4  4.O    " 

\  4.50 

15  

16  

I.OOA.  M 
2.  2O     4< 

15  

16  

4.40     " 

4  40    " 

3.40 

2  2O 

17 

No  light 

17    . 

No  light 

O  OO 

IS  

No  light. 

18  

No  light. 

O  OO 

IQ     . 

No  light 

IQ  . 

No  light 

O  OO 

20  
21  

6.  30  P.  M. 
6.30    " 

20  
21  

8.40P  M. 
910   " 

2.10 
2  J.O 

22  ... 

6  'j.o    " 

22 

Q   ^O     " 

3  2O 

2-3  .  . 

6.30   " 

2^  .  . 

IO  ^O     " 

A  OO 

2J.     . 

6  T.O   " 

2  J.  . 

II   2O     " 

4  en 

25  

6.  20   " 

26  

12.  2O  A.  M. 

6  oo 

26    

6.  20    " 

27  .        ... 

I  2O    " 

7  OO 

27  

6.  20    " 

28  

2.  2O     " 

8.00 

28     

6.  20    " 

2Q 

n.  2O    " 

9  oo 

2n 

6  20    " 

on 

4  2O    " 

IO  OO 

3O  

6.10    " 

Oct.  i 

^  .  OO     " 

IO  £^O 

Total  number  of  hours, 


181.40 


The  foregoing  schedule  was  calculated  on  the  following  basis: 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


DYNAMO   TENDERS'  HANDBOOK. 


OCTOBER. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
2  

H.  M. 
6.IOP.  M. 

6  10    ' 

2.  ..... 

o 

H.   M. 
5.  00  A.  M 

5  oo    '  ' 

H.    M. 
10.50 
IO  ^O 

3   

6  10    " 

A 

c,  oo    " 

10  50 

4  

6.10   " 

C 

c  CO    " 

10  50 

5   

6  10    " 

6 

5  oo   " 

10  50 

6  

6.  10    " 

7 

c  OO     " 

10  50 

7  

7  OO    " 

8 

c  OO     il 

IO  OO 

8  

7.40    ' 

5  .  oo   " 

Q  2O 

8  30    " 

10 

e   TO     " 

8  40 

10  

9.  ^o    '  ' 

ir         ... 

c,  10    " 

7  jo 

ii  .... 

10  40    ' 

12 

c    TO     *' 

6  30 

12  

II  CQ    " 

) 

1-2 

TO 

5    TO     " 

\  5.20 

14  

JC 

I.IOA.M. 
2  ^O     " 

14..  

T  c 

5.10   " 
510   l4 

4.00 

2  zlO 

]6  

No  light. 

16     .  . 

No  light 

o  oo 

17  

No  light. 

17  

No  light- 

o  oo 

18  

No  light 

18. 

No  light 

o  oo 

19   
20  

5.40P.M. 

C   J.Q     " 

19  

20.    . 

7.  40  P.  M 

8  20     " 

2.00 
2  J.O 

21  

5.40     ' 

21  .        . 

Q  JO     " 

•5     <5O 

22       .             ... 

c  40     tf 

22 

IO  IO    " 

J.  ^O 

23    

5-4°    ' 

2^.  . 

II.  TO     " 

c   7Q 

2d 

c  J.Q     " 

2C 

12  IO  A.  M 

6  30 

25     

5.40    " 

26  

I.IO     " 

7  qo 

26            

5.40    " 

27    

2  IO     " 

8  30 

27    

5.30    " 

28  

3.IO    " 

Q  4O 

28       

5.30    " 

2Q    . 

4  10   " 

10  40 

2Q.  . 

5.30    " 

30  

S.io   " 

II  40 

^o  . 

5.30    " 

31        .... 

5  30    " 

1°  OO 

^1  

5.  so   " 

Nov.   I  .  . 

^.30     " 

12  OO 

Total  number  of  hours, 


215-50 


The  foregoing  schedule  was  calculated  on  the  following  basis : 
Light  one-half  hour  after  sunset  and   one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


LAMP   LIGHTING   SCHEDULE. 


NOVEMBER. 


Day  of  Month. 

Light. 

Day 

of  Month. 

Extinguish. 

Number  of 
Hours. 

I  
2                    ... 

H.  M. 

5.  30  P.  M. 
c  qo     " 

2  

-2  .   . 

H.  M. 

5-  30  A.M. 
e  ao     " 

H.  M. 
12.00 
12  GO 

e  an     " 

e   ao     '  ' 

12  OO 

A 

^.20     " 

C      . 

e  40     " 

12  2O 

e   2O      " 

6     

SAO      " 

12  2O 

6     .  .      ... 

7  20    " 

7  

c   do     " 

IO  2O 

7  

8.30    " 

8  

C.4O     " 

Q  IO 

8      

Q.4O      " 

e  AQ     " 

8  oo 

10  50    ' 

) 

10  

10  

C    AQ       " 

\     6-50 

ir  

12     

1  2.  10  A.M. 
I  2O     " 

ii  

12    

5-40       ' 
C.    AQ       " 

5-30 

A    2O 

I  3    . 

2  J.O     " 

I  -7 

c   40     " 

a.  oo 

14       

3.50     ' 

14    

e   CQ     " 

2  OO 

I  c 

No  li^lit 

1C 

No  light 

o  oo 

16   

No  lifrht 

16   

No  lio-ht. 

o  oo 

17  .. 

No  light 

17 

No  Jight 

o  oo 

18  

IQ     . 

5.10  P.  M. 

Z   IO      " 

18  

IQ 

7.  50  p.  M. 
8  50    " 

2.40 

q  J.O 

2O  

5.IO      ' 

2O                    ... 

o  ao     " 

4  20 

21  ....       . 

5    IO      " 

21 

II  OO     ' 

C     CQ 

22 

e   10     " 

22 

12  OO      " 

6  50 

2^ 

5.TO     ' 

24 

I   OOA    M 

7  ^O 

24 

%   IO      " 

2C.  . 

2  OO      " 

8  50 

2^    . 

^.IO     " 

26  .::::: 

a  OO     " 

*       Q  ^O 

2|    ....:. 

^   IO 

27 

4  oo    " 

10  50 

27  

D          ,. 

^.IO      ' 

28  

•>  OO     " 

IT.5O 

28    

D          .. 

Z    IO 

2Q 

6  oo    " 

12   50 

2Q  

,, 

^.IO 

30  

6  oo    '  : 

12  =;o 

on   . 

0 

'i.OO 

Dec.  i. 

6  oo    " 

13  oo 

Total  number  of  hours, 


2.21.00 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


DYNAMO  TENDERS'  HAND-BOOK. 


DECEMBER. 


Day  of  Month. 

Light. 

Day 
of  Month. 

Extinguish. 

Number  of 
Hou-  s. 

I  
2  .  .  ".  

H     M. 
5.  OOP.  M 
c   OO     *' 

2  

3  

H.    M. 

6.  10  A  M. 

6.  10    " 

H.   M. 
I3.IO 
I'}   IO 

o  .  . 

5  oo   ' 

4  .  . 

6  10    *' 

13  10 

4  

c  QO     " 

5  

6.  10    " 

11   IO 

7-20     " 

6   

6  10   " 

10  40 

5.  .  . 

6  

8  4O     " 

7  

6.10   " 

Q  1O 

7 

I  O  OO     '  ' 

8     ... 

6  10   " 

8  10 

8 

1  1   IO     '  ' 

) 

6  10    " 

j.     7.00 

10  

j  i 

12.  2O  A.  M. 
T   1O     '  ' 

10  

ii  .... 

6.10   " 
6  10    " 

5-50 

A   AQ 

12 

2   ^O     '  ' 

12  

6.  20   " 

q  -20 

13  

4  oo    " 

13  

6.  20    " 

2.  2O 

I  J. 

No  light 

14  

No  light. 

O  OO 

m   . 

Noli^ht 

15  

No  light. 

O  OO 

16.  .  .  . 

No  light 

16  

No  light. 

O  OO 

i?  

18 

5.  oo  P.  M 

5    TO     " 

17  
18  

7.40P.M. 
8.40    " 

2.40 

•3    ^O 

IQ  .  . 

cio    " 

IQ  .  . 

Q.^o    " 

4.40 

2O 

^   IO     ' 

2O     .... 

10.50    " 

^.40 

21 

c    jo     " 

21  

11.50    '* 

6.40 

2°             .  .  • 

5    jo     '  ' 

27 

12  50  A.  M. 

7.40 

21 

5IO     '  ' 

24.  .  . 

I.5O     " 

8.40 

2/1 

C    TO     <; 

2C 

2.5O     " 

Q.  J.O 

2C 

C    TO     '  ' 

26  

3.50    '* 

10.40 

26 

r    TO     '  ' 

27 

4.50    i( 

11.40 

27 

5    TO     '  ' 

28  

6.00   " 

12.50 

28 

c    JO     '  ' 

2Q 

6.  20   *' 

13.  10 

2Q  .  . 

5.IO     ' 

3O.  .. 

6.20     " 

13.10 

ao    . 

^    IO     " 

31  

6.20     " 

13.10 

11.  . 

=;.io  " 

Tan.  i.  '02 

6.  20    " 

13.10 

Total  number  of  hours, 
Grand  total  of  lighting  hours, 


241.20 
2197.40 


The  foregoing  schedule  was  calculated  on  the  following  basis  : 
Light  one-half  hour  after  sunset  and  one  hour  before  moonset. 
Extinguish  one  hour  after  moonrise  and  one  hour  before  sunrise. 


CONSTRUCTION    TOOLS. 


PQ 
o 

J5 

O 
O 

Q 
I 


I 


PQ 
O 


38 


EXX  HAND-BOOK. 


o 
o 


O 
vn 

6 


CONSTRUCTION    TOOLS. 


89 


90       DYNAMO    TENDERS'  HAND-BOOK. 


CONSTRUCTION   TOOLS. 


U 

0 

g 
u 
13 


o 

£ 


DYNAMO    TENDERS' 


-K-sssa" 

* 

FIG.  68. — MICROMETER  GAUGE. 


FIG.  69. — STANDARD  WIRE  GAUGE. 


FIG.  70  —TAPE  LINE. 


WIRING HA-BOOK 

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